"2009 is suddenly a holiday of racers. If you don't believe that, consider the trifecta that dropped--or will drop--shortly: Need For Speed: Shift, Dirt 2, and Microsoft's holiday tentpole Forza Motorsport 3. All of them promise realistic physics, blazing speeds, and tons of customization, but NFS: Shift and Dirt 2 are multiplatform, while Forza Motorsport 3 is an Xbox 360 first-party exclusive. For my money, though, I'll take Forza 3. After playing all three, the newest Forza has, surprisingly, won me over--not with realism, but with fun.
From a pure car enthusiast's perspective, I'm not sure any game other than Gran Turismo 5 can do any better. Car exteriors and interiors are immaculately rendered, and the 60-frames-per-second graphics make animations and the entire racetrack environment look hyperreal."