I have gone through more keyboards than I can count (I was into keyboards before I got into the mechanical version). See sig for current lineup (I also have an Apple aluminum keyboard that I use on my recording computer).
Previously I've gone through a Das Keyboard, 3 Filcos, 2 QFRs, 3 RealForces, a HHKB, another FC660C, 3 Poker X's, 3 ErgoDoxes, a Matias Tactile Pro 3, a Unicomp Ultra Classic, two Dell AT101Ws, and probably a few more I can't remember. That's just since joining GH in 2010. Before that I'd gone through pretty much all the MS Ergo boards and Razer boards, a Creative Fatal1ty keyboard, a few EluminX boards, and a bunch of things like iRocks and Auravision.
I'm not sure when I'll stop. I love typing way too much. Next up: AcidFire's Axios/Nexus, the Keyboard.io Model 01, and (just because I have a soft spot in my heart for chiclet-style scissor switches), probably a Razer DeathStalker.