Too many to list, way, way too many.
My major ones, though:
Shadowrun- pretty much my favorite handling of cyberpunk, and the books are amazingly fun to read dude to the BBS format most all of them have.
D&D 4th Edition- Before an edition war sparks, I like 3.5 and even AD&D just fine, I just like 4th ed BETTER
Legend of the Five Rings/7th Sea- both made by the same company, feudal Japan for the first, age of sail/exploration Europe for the second. Smooth, cinematic system and well written books make it a great game to run and play.
Warhammer Fantasy Roleplaying Game/Dark Heresy/Rogue Trader- all from the same company again, based on the wargames Warhammer Fantasy Battles and Warhammer 40k, great system and fun to play.
nWoD- Old World of Darkness was a pretty rough system with terrible writers, the new system removed most of the terrible writers (but oh lord they manage to slip back in some times and it shows), and the crunch got about a billion times better.
And of course all manner of other RPGs that catch my group's interest.