In recent years it's really just been some Castles & Crusades and a little bit of 3rd edition D&D before that. Going back a little further we've got some Hero system and (separately) FUZION supers.
Back in the 90s I wound up playing more GURPS stuff than anything else. Except for the early 90s when there was some hybrid 1e/2e AD&D and a wonderful Justice, Inc. pulp campaign. That's pre-unified Hero rules for those who don't recognize the name.
Headed back into the 80s it was TFT (ah, sweet TFT), LBB Traveller, 1e AD&D, Moldvay Basic/Expert D&D, and much Champions. Throw in some brief flirtations with Villains & Vigilantes, Daredevils and Top Secret and I think that's really it for actual playing. There's a whole bunch of stuff I've owned but never really got to do anything with - running the gamut from Bunnies & Burrows to Big Eyes, Small Mouth with countless weird stops in between.
Hey! There's something missing in there. Actually, no. As odd as it is (given that I'm here now) I never really played any Runequest or CoC or other BRP games. I always thought the system was neat, but no one else around me was really playing it. So I'd look over my Superworld, WoW and BRP books, sigh, and then put them away for the mythical rainy day. Which never came around. Until now