I'm just coming down of a Dark Age of Camelot addiction. I used it to bounce back after a Diablo 2 addiction, which was a bounce back from my classic Diablo addiction.
I also like Unreal Tournament, UT2003. (anybody else actually kind of like the old UT better?)
I've also played Ultima Online, which was cool, I haven't played it in like 3-4 years though. I've also played Everquest which I didn't play long (and I've thought about trying it again) and I've played Shadowbane which I think totally sucked. Right along with Star Wars Galaxies.
On console games my old favorities where:
NES : Faxanadu was by far the greatest. There was also Mike Tysons Punch Out, The Legend of Zelda, SuperMarioBros, Ninja Gaiden, Rad Racer, Battletoads, Teenage Mutant Ninja Turtles, and a few more I'm sure.
Super NES: SupMario3, Super Punch Out. Street Figher 2 Turbo, Mortal Kombat 2, Legend of Zelda Link to the Past?, and Killer Instinct, TMNT Turtles in Time.
I'm mostly into the PC games now though, as I like the online playing experience.