I'll admit it! I have a regular group (Sundays) that plays mostly Pathfinder, using Paizo's Golarion campaign setting. Formerly we used D&D 3.5 and, before I joined, I'm pretty sure the same folks have been playing all of the editions since 1e in various combinations (30+ years I guess). We also mix it up with GURPS and other game systems from time to time. I play with a different group on Mondays and it's a mix of genres and systems including stuff like: Deadlands, Firefly (using Deadlands), Gamma World, Call of Cthulhu (D20 and CoC and, soon, Gumshoe), and Star Wars (Saga).

I'm not stuck on any one fantasy setting but I like Golarion well enough. I do also like Eberron (I've only run one game in it) and Dark Sun (never played but my co-DM is a big fan and I've been trying to get her to run something there). Some of the other old TSR settings are interesting to me as well, especially Ravenloft. Truthfully, though, I prefer sci-fi...especially post-apocalyptic...to fantasy. I don't get to play a lot of it but we try to insert it into the schedule whenever we can. I've got plans to run a Star Trek game at some point after we finish our current long-running fantasy campaign I've been running (Paizo's Rise of the Runelords, we're on the last book).

We play a lot of D20 but it's definitely not my favorite system. I like GURPS best, I suppose, with a nod to Deadlands if it happens to match the feel of the game (it worked super awesomely for Firefly).
M