Burnout Paradise is widely regarded as Criterion Games' best title and with damn good reason. It's also one of the few racing games out there that manages to faithfully provide its players with the recreation of a city that not only feels real, but real enough to make you want to drive around just for the sake of driving around. That's pretty important for a game that's solely about racing.
As the game is set in an open world environment, so too are its tracks which are simply portions of the open world cordoned off for the purpose of racing. Drivers can even go online to participate in open world races or simply mess around with others.
Racing games just don't get any better than this.
System requirements:
Operating system: Windows XP / Vista / 7
Processor: Quad Core running at 2.8 GHz or equivalent
Memory: 1 GB
Hard diske: 4 GB
Sound Card: Sound Card compatible with DirectX 9.0
Graphics Card: GeForce 8600 or Radeon X1950, (256 MB) / GeForce GTS 250 or Radeon 4850 (512MB)