Here you have my first post of a competitive doubles team. I think that synergy is one of the most important aspects when playing doubles and I hope that you enjoy my strategy. Recently, I posted this team on the Serebii forums, but didn't receive too much help, so I'm hoping that you can help me out with a few things. Intelligent comments are welcomed. Images from The Pokemon Factory.
Gengar@Wide Lens
Timid Nature
Levitate
6 HP - 252 Sp Atk - 252 Spe
=Hypnosis
=Will-o-wisp
=Shadow Ball
=Focus Blast
Gengar is a good lead for my team that works well with most of its partners. Wide Lens helps boost accuracy and Levitate prevents it from Marowak and Gyarados' Earthquake attacks. Double status for support - depending on the pokemon - and Shadow Ball/Focus Blast for type coverage. I like using him for the opening turn, when many opponents tend to Fake Out my other lead. I then put the biggest threat to sleep or cripple its attacking power. Once I have afflicted one or more of my opponents pokemon, it is time for Gengar to retreat (I haven't had many issues with Pursuit in doubles). From now on, Gengar is my counter for explosion teams and switches into Ground/Fighting/Normal attacks for other pokemon. So far, he has worked well with the "hit and run" strategy.
Gyarados@Wacan Berry
Adamant Nature
Intimidate
216 HP - 16 Atk - 176 Def - 100 Spe
=Dragon Dance
=Taunt
=Waterfall
=Earthquake/Return
A BulkyGyara set that works very well as a lead. Intimidate cuts BOTH of the opponents' attack stats. If I suspect a Fake Out on turn one, I let Gyara take it, while Gengar puts the biggest threat to sleep. Then, Gyara is free to Dance for a couple of turns and Taunt leads who rely on status/Stealth Rock support. However, I sometimes decide not to Taunt the oh-so-common Trick Room leads because I have a nasty surprise for them...
Marowak@Thick Club
Brave Nature
Lightningrod
252 HP - 252 Atk - 6 Def (0 Speed IVs)
=Protect
=Earthquake / Bonemerang
=Ice Punch
=Fire Punch
This is my Trick Room counter. TR teams dominate the doubles metagame, so I spent time looking for a decent Marowak with a 0 speed IV. This Marowak is slower than most things and has a top speed of 85. Earthquake is for STAB, Ice Punch for dragons, and Fire Punch for Bronzong. Lightningrod is a very useful ability for my team, because of its many Water and Flying types. Marowak is also fun to switch in for Gengar if I suspect an electric attack the next turn (targeting Gyarados). Then Marowak can usually Protect as both opponents attack the biggest threat, giving Gyarados another turn to setup.
Zapdos@Leftovers
Timid Nature
Pressure
252 HP - 220 Def - 38 Spe
=Discharge
=HP Ice / HP Grass
=Light Screen
=Roost
Zapdos is a wonderful pokemon - it has only 2 weaknesses, is immune to EQ (when not Roosting), and can provide support to the team. Discharge has a great 30% paralysis rate that cripples opposition. This still hits both opponents, despite Marowak's ability. HP Ice is for coverage, but HP Grass is my only way to deal with Swampert... and Light Screen provides excellent team support for Marowak and friends to take a special hit. Between Gengar's status afflictions and Zapdos' 30% paralysis rate, the opposition suffers from crippling conditions. ***Should I use the Defensive Roost Zapdos, or the Special Sweeper Zapdos?***
Lanturn@Leftovers
Bold Nature
Volt Absorb
EV: 196 HP - 192 Def - 122 Sp Def
=Stockpile
=Thunder Wave/Discharge
=Confuse Ray/Rest
=Brine/Water Pulse
Lanturn is one of my favorite pokemon, and fits perfectly into this team. The EV spread above gives Lanturn a HP of 440 and roughly equal defensive stats of 220. Most opponents do not see Lanturn as a threat and ignore it for several turns. During this time, Lanturn can Stockpile, giving it godly defenses. Thunder Wave works well, as long as Marowak is not my partner, so Discharge is listed. Confuse Ray + Brine works really well to slowly weaken pokemon, but Rest + Water Pulse provides recovery and a chance of confusion. Lanturn is a great defensive pokemon - especially with a few Stockpiles under its belt. It is great to switch into, and then if I suspect an Earthquake, switch the fish for Gyarados, Zapdos, or Gengar.
Golduck@Wide Lens
Modest Nature
Cloud Nine
6 HP - 252 Sp Atk - 252 Spe
=Protect
=Hydro Pump
=Focus Blast
=Disable / Ice Beam / Blizzard
The three most common doubles strategies are Trick Room, Explosion, and Weather. Golduck is my secret weapon for weather-based teams. What happens when poor Kingdra no longer has Swift Swim boosts and is paralyzed by Zapdos' Discharge while Golduck Protects? What happens when Cherrim folds back up in its flowery bud and Exeggutor's speed is reduced to null? Oh no, now Glaceon's Blizzard wont always hit and Tyranitar no longer has a Sp Def boost! These are the reasons I carry Golduck - the weather team destroyer. Protect is there for Discharge with my team, Hydro Pump gets nice STAB against Hippowdon, and Focus Blast destroys Tyranitar without its Sp Def Boost. Disable is fun to use on the switch-in to antagonize weather teams who rely on one major move. Golduck does not have the best stats available, but its ability is what makes it shine.
Here is a breakdown of how my partners work with each other:
Gengar + Gyardos = A good lead that distracts Fake Out users, while Gengar inflicts status.
Gengar + Marowak = Marowak is free to EQ while Gengar inflicts status.
Gengar + Zapdos = Not an ideal combination, but Zapdos provides Team Support, while Gengar provides more special coverage.
Gengar + Lanturn = Lanturn works as the support pokemon while Gengar sweeps.
Gengar + Golduck = Nothing special here, but it works.
Gyarados + Marowak = Deadly combination. Marowak draws electric attacks away from Gyarados while Gyara sets up for a sweep. (Marowak has Protect for Gyara's EQ).
Gyarados + Zapdos = I try to avoid this combination due to Discharge, but Gyara is also free to Earthquake, while its Wacan Berry saves it from damage (but not paralysis).
Gyarados + Lanturn = Gyara provides an Intimidate to help Lanturn's tanking abilities, while Lanturn paralyzes the opponent for Gyara's sweep. Watch out for EQ here.
Gyarados + Golduck = Double Sweepers that can take down most weather-based teams.
Marowak + Zapdos = A wonderful combination. Zapdos gives Marowak a sp def boost while Marowak EQs away (except on a roost turn).
Marowak + Lanturn = Works decently if Lanturn carries Discharge. Then Marowak has a chance to move first - however, those EQs are painful.
Marowak + Golduck = Marowak can EQ while Golduck Protects, or Golduck can Disable while Marowak Protects. Nice duo.
Zapdos + Lanturn = Time to shine! Lanturn is healed 1/4 of its health each time Zapdos uses Discharge and also has a good chance of paralyzing enemies. This is one of my favorite combos!
Zapdos + Golduck = Golduck has Protect for a reason! This is great to take out Rain Dance-based teams.
Lanturn + Golduck = Thunder Wave + Disable + Confuse Ray = Annoying and effective.

Gengar@Wide Lens
Timid Nature
Levitate
6 HP - 252 Sp Atk - 252 Spe
=Hypnosis
=Will-o-wisp
=Shadow Ball
=Focus Blast
Gengar is a good lead for my team that works well with most of its partners. Wide Lens helps boost accuracy and Levitate prevents it from Marowak and Gyarados' Earthquake attacks. Double status for support - depending on the pokemon - and Shadow Ball/Focus Blast for type coverage. I like using him for the opening turn, when many opponents tend to Fake Out my other lead. I then put the biggest threat to sleep or cripple its attacking power. Once I have afflicted one or more of my opponents pokemon, it is time for Gengar to retreat (I haven't had many issues with Pursuit in doubles). From now on, Gengar is my counter for explosion teams and switches into Ground/Fighting/Normal attacks for other pokemon. So far, he has worked well with the "hit and run" strategy.

Gyarados@Wacan Berry
Adamant Nature
Intimidate
216 HP - 16 Atk - 176 Def - 100 Spe
=Dragon Dance
=Taunt
=Waterfall
=Earthquake/Return
A BulkyGyara set that works very well as a lead. Intimidate cuts BOTH of the opponents' attack stats. If I suspect a Fake Out on turn one, I let Gyara take it, while Gengar puts the biggest threat to sleep. Then, Gyara is free to Dance for a couple of turns and Taunt leads who rely on status/Stealth Rock support. However, I sometimes decide not to Taunt the oh-so-common Trick Room leads because I have a nasty surprise for them...

Marowak@Thick Club
Brave Nature
Lightningrod
252 HP - 252 Atk - 6 Def (0 Speed IVs)
=Protect
=Earthquake / Bonemerang
=Ice Punch
=Fire Punch
This is my Trick Room counter. TR teams dominate the doubles metagame, so I spent time looking for a decent Marowak with a 0 speed IV. This Marowak is slower than most things and has a top speed of 85. Earthquake is for STAB, Ice Punch for dragons, and Fire Punch for Bronzong. Lightningrod is a very useful ability for my team, because of its many Water and Flying types. Marowak is also fun to switch in for Gengar if I suspect an electric attack the next turn (targeting Gyarados). Then Marowak can usually Protect as both opponents attack the biggest threat, giving Gyarados another turn to setup.

Zapdos@Leftovers
Timid Nature
Pressure
252 HP - 220 Def - 38 Spe
=Discharge
=HP Ice / HP Grass
=Light Screen
=Roost
Zapdos is a wonderful pokemon - it has only 2 weaknesses, is immune to EQ (when not Roosting), and can provide support to the team. Discharge has a great 30% paralysis rate that cripples opposition. This still hits both opponents, despite Marowak's ability. HP Ice is for coverage, but HP Grass is my only way to deal with Swampert... and Light Screen provides excellent team support for Marowak and friends to take a special hit. Between Gengar's status afflictions and Zapdos' 30% paralysis rate, the opposition suffers from crippling conditions. ***Should I use the Defensive Roost Zapdos, or the Special Sweeper Zapdos?***

Lanturn@Leftovers
Bold Nature
Volt Absorb
EV: 196 HP - 192 Def - 122 Sp Def
=Stockpile
=Thunder Wave/Discharge
=Confuse Ray/Rest
=Brine/Water Pulse
Lanturn is one of my favorite pokemon, and fits perfectly into this team. The EV spread above gives Lanturn a HP of 440 and roughly equal defensive stats of 220. Most opponents do not see Lanturn as a threat and ignore it for several turns. During this time, Lanturn can Stockpile, giving it godly defenses. Thunder Wave works well, as long as Marowak is not my partner, so Discharge is listed. Confuse Ray + Brine works really well to slowly weaken pokemon, but Rest + Water Pulse provides recovery and a chance of confusion. Lanturn is a great defensive pokemon - especially with a few Stockpiles under its belt. It is great to switch into, and then if I suspect an Earthquake, switch the fish for Gyarados, Zapdos, or Gengar.

Golduck@Wide Lens
Modest Nature
Cloud Nine
6 HP - 252 Sp Atk - 252 Spe
=Protect
=Hydro Pump
=Focus Blast
=Disable / Ice Beam / Blizzard
The three most common doubles strategies are Trick Room, Explosion, and Weather. Golduck is my secret weapon for weather-based teams. What happens when poor Kingdra no longer has Swift Swim boosts and is paralyzed by Zapdos' Discharge while Golduck Protects? What happens when Cherrim folds back up in its flowery bud and Exeggutor's speed is reduced to null? Oh no, now Glaceon's Blizzard wont always hit and Tyranitar no longer has a Sp Def boost! These are the reasons I carry Golduck - the weather team destroyer. Protect is there for Discharge with my team, Hydro Pump gets nice STAB against Hippowdon, and Focus Blast destroys Tyranitar without its Sp Def Boost. Disable is fun to use on the switch-in to antagonize weather teams who rely on one major move. Golduck does not have the best stats available, but its ability is what makes it shine.
Here is a breakdown of how my partners work with each other:
Gengar + Gyardos = A good lead that distracts Fake Out users, while Gengar inflicts status.
Gengar + Marowak = Marowak is free to EQ while Gengar inflicts status.
Gengar + Zapdos = Not an ideal combination, but Zapdos provides Team Support, while Gengar provides more special coverage.
Gengar + Lanturn = Lanturn works as the support pokemon while Gengar sweeps.
Gengar + Golduck = Nothing special here, but it works.
Gyarados + Marowak = Deadly combination. Marowak draws electric attacks away from Gyarados while Gyara sets up for a sweep. (Marowak has Protect for Gyara's EQ).
Gyarados + Zapdos = I try to avoid this combination due to Discharge, but Gyara is also free to Earthquake, while its Wacan Berry saves it from damage (but not paralysis).
Gyarados + Lanturn = Gyara provides an Intimidate to help Lanturn's tanking abilities, while Lanturn paralyzes the opponent for Gyara's sweep. Watch out for EQ here.
Gyarados + Golduck = Double Sweepers that can take down most weather-based teams.
Marowak + Zapdos = A wonderful combination. Zapdos gives Marowak a sp def boost while Marowak EQs away (except on a roost turn).
Marowak + Lanturn = Works decently if Lanturn carries Discharge. Then Marowak has a chance to move first - however, those EQs are painful.
Marowak + Golduck = Marowak can EQ while Golduck Protects, or Golduck can Disable while Marowak Protects. Nice duo.
Zapdos + Lanturn = Time to shine! Lanturn is healed 1/4 of its health each time Zapdos uses Discharge and also has a good chance of paralyzing enemies. This is one of my favorite combos!
Zapdos + Golduck = Golduck has Protect for a reason! This is great to take out Rain Dance-based teams.
Lanturn + Golduck = Thunder Wave + Disable + Confuse Ray = Annoying and effective.