Good racing games?

Need for speed

The Fast and the Furious 6

lol jokes.

Do you want sim or arcade or a mix?

Depends if you want simulation or arcade,
arcade would be: need for speed, burnout paradise
sim : try iracing

my favorite are the dirt series games

Dirt 3 and Burnout Paradise are good ones.

I'd give you some suggestions, but you're only looking for opinions. Everything I say is fact.

Driver San Francisco

Burnout Paradise

DiRT 3, Driver San Francisco, Need for Speed Hot Pursuit and MX vs ATV Reflex.
If you want a classic, try the good ol' PS2's Downhill Domination.

Its been a long freaking time but I had fun with midnight club 2, which is apparently on steam

GRID for real racing

F1 2012 for even more real racing

F1 Race Stars / Sonic & All Star Racing Transformed for Fun Kart Racing

Burnout Paradise / NfS Most Wanted (the old one) for Fun Racing

Big Rigs

TrackMania² Stadium.

Dirt 2

Need for speed world

just don't get Ridge Racer Unbounded. such a disappointment.

Burnout Paradise if you like arcade. xP

oh oh oh
FLATOUT GUYZ :>

Secret of the Magic Crystals

Grid is good also

blur

If you can live with Non Steam (since it was removed some time back), look up Outrun 2006. Midnight Club 2 is great if you want Steam.

FlatOut Ultimate Carnage - best arcade racing I have ever played.

This may sound a bit odd, but try Kororinpa on the Wii. Yes, it's a marble roller, but you race along the track against the clock and the marbles are all different. The grounds you are rolling on are different too, with distinctive sound and rumble effects on the controller. This game had the best experience in simulating rolling on wood, grated metal, cookies and everything. Great sense of speed and force too.

If you want a good arcade racer go with both GRID games.
If you want simulation at it's best go with rFactor or Raceroom Racing Experience.