from the Topre wiki guide here on geekhack, a professional FPS gamer likes his topre realforce board, link here:
http://geekhack.org/showthread.php?t=8872I can attest to that strictly for gaming.. the topre 55g is a great board (i have one for sale in my sig too >.<) but after a long period of typing it may hurt your fingers..
they have the normal variable board.. but the 'a' key which is commonly used for moving your character around is 35g which is a little bit annoying but can adjust to. you can also "mod" your keyboard (also in the topre wiki) so that it's 45g like the rest of the keys.
(i've tried both boards). and they're also unique in the way that as soon as the key gets pushed down the slightest bit, the key gets registered.. so that might take some adjusting to do but i haven't found any problems with gaming what so ever with it and i love this board. the only down side is the price..
basically topre's feel like the best rubber dome a manufacturer can ever make.. it's like a very sturdy rubber dome board.. don't know how to explain it, but if you use the search function you can get a better description from others.
if you go the mechanical route.. (i tried blues and browns) i'd suggest browns. the keys are light.. more so if you're coming from a rubber dome board like i did.. but you get used to it for a while.
they say blacks are the best for FPS gaming though but if you're doing alot of typing (just like the 55g topre board) you're fingers might hurt if you're not heavy handed
i've been a big time PC gamer my whole life.. FPS/RTS/MMO so i can relate to your questions