Realistic PC Racing Simulators?

I've seen a few threads around the Games section which listed a few but I can't find them under the search. Sorry I didn't catch it.

I was looking for a pretty realistic racing simulator with very good graphics, great sound, and realistic handling. I've been looking for a game out there with a Gran Turismo type setup, similar cars, tracks, racing style .. etc. Anybody care to help me out?

rFactor is great & my personal fav. Lots of really good mods for it too. Panoz Esperante GTS on Road Atlanta = awsome!
Live for Speed, GTR, GTR2, GT Legends are all very good sims.