First off, I absolutely agree with wired gaming. I have another keyboard for that.
However , I thought it would be nice to experiment a bit. I am personally adding a slim/minimalistic keyboard to my office/PS3 area, and would love to have this keyboard to handle moderate gaming back on my main PC.
So far there are two wireless keyboards I am interested.
I think if you're FPS gaming, you'll be fine with those, but if you do RTS and things that require finding certain buttons and pushing ctrl and shift on both sides of the board, the button configuration won't be the easiest to use. FPS would be fine because its WASD and your hand never really moves form that position.
I have never used these keyboards, I am just basing this on looking at them.
I have been looking for a cheap keyboard, and I came across this:
It's not wireless, and not a gaming keyboard, but it comes with alternate WASD keys, up to 1000Hz polling, and you can have 11 keys pressed at once, so no conflicting with your ctrl+w+a+r and 7 more buttons at once and its super cheap. Also I hear that Rosewill has excellent customer service.