Vengeance K90 raises the bar to new heights for gaming and mechanical keyboards alike, but could stand to lose its dome-switched function keys that greatly diminish the backlighting and feel. A driver and firmware update couldn't hurt either.
The Logitech G510 is the reincarnation of the original legendary G15 gaming keyboard, just with more power and more abilities than ever before. If you can afford the best, this keyboard should be at the top of your list.
G110 is a worthy successor to the G11 for macro junkies who don't have a need for an LCD but want all the other frills gaming keyboards have to offer. The only disappointment is the omission of a green backlighting channel.
MS Sidewinder X6 is a great gaming / casual keyboard for the control-freak in all of us with real-time macro recording functionality, an admirable design and color scheme, and deserves credit for improving on its predecessor.