My first RPG was D&D back in the '70s.
Keep on the Borderlands, cheap plastic dice with hand-packed crayon in the numbers, THAC0, Pet/Poly, Rod/Staff/Wand, etc.
Since then I've played and DM'ed (in no particular order) Gamma World, AD&D, 3E, 3.5, Pathfinder, Roll Master, Champions, Fantasy Hero, Warhammer Fantasy, Fantasy Craft, Spy Craft, GURPS, Ritfs, Vamipre: TM, Star Wars D6 & d20, Pelicar, and probably 10 more that I can't think of right now...
I've also played just about every MMORPG: Ultima Online, Everquest, Dark Age of Camelot, Asheron's Call, Star Wars Galaxies, World of Warcraft, Guild Wars, and many many more.
I tend more toward fantasy, especially classic Tolkein or Howard style high fantasy or sword and sorcery. Lower magic and medieval tech as opposed to super-hero magic or gunslinger stuff.
I do like the occasional sci-fi or super hero genre game from time to time as well. Just not in my fantasy.
I eventually stopped running Pathfinder in favor of Fantasy Craft, but I've now converted back to Pathfinder with the second edition.