Here are some banners from my trade thread. Comments?
Overall, not too bad, but a few nitpicks:
As soraryuu said, you have font problems. Try not to use the exact same font for every banner, and you want font to be clear if its a banner. sigs are something else.
the icons in the bottom left corners are unnecessary, and take some attention away from the main banner. if its your "signature" or something, you could maybe turn the opacity down to ~30%, so its barely visible. Personally i never do this, and i don't see the point anybody else does.
The sprites are also unnecessary, because they don't really add anything to the banner, and once again, takes attention away from the main render and text.
EDIT: render was so sexy i couldn't resist