Steam has all the Codemaster racing games 75% off, and a whole package deal thing.
This includes Dirt, Dirt 2, Grid, Fuel and Toca Race Driver 3.
The Dirt series is a pretty solid arcade off road racing game. If you're looking for a real rally experience you might be a tad disappointed at the short stages, but the games, particularly dirt 2 are absolutely gorgeous, and the racing is easy enough to pick up since the controls/physics are pretty forgiving and arcadey.
Grid is also pretty solid, they have a decent cross-section of cars and race types. If you're looking for a real in depth sim game you'll be disappointed, but it's like "DIRT" on pavement. Arcadey-sim lite style racing.
Fuel I've played a demo of and wasn't impressed. The world is huge, but the graphics are splotchy and the driving mechanics just don't click right. The tracks are somewhat littered with annoying obstacles that can completely hose your rune. Though it's for sale for like 5 bucks, and it's probably worth that much.
Toca I haven't tried and will likely be picking up with this deal, even if it is an older game.
....I'm not sure how many other racing game players are on these boards and would care about this though.