I like to see:
1. Power-ups: As long as they're not too powerful (like bullet bill), they make the game more fun.
2. Chases: If it's like NfS: Nitro and there are cops chasing, that definitely adds to the thrill.
3. Ability to reach high speeds: If the cars can't cross at least 100 mph on the speedometer then the game seems too slow.

What about you? What features do you like to see in racing games?

I'm surprised to see that no one else replied to this interesting thread. Anyways, I'd probably like to see:

1. Awesome variety of amazing vehicles to drive. 
2. Cool and different challenges. (Not only the original racing but other certain challenges with it.)
3. And power-ups that are not too overpowered. 

Thats about it for me.

I like to see good gameplay, with cars that have stats that make the faces even. I like to see fancy cars or real cars. If it is too easy, I don't want to play it as I don't like blowing everyone out.

Put simply a good time!  Racing games are one of my favorite genres but to put a finger on what makes the great ones great is hard for me to do.  From Mario Kart for Snes to Forza IV or Dirt what makes a racing game fun can differ so greatly I don't know what I'd like to see other than some fun.  Maybe I wanna fling a turtle shell at the leader or realistically spit dirt in your face as long as it is fun.  I don't think you can put a formula on what makes a good racing game and that is part of what makes the genre so great.

In a racing game, I would like to see a large assortment of cars and I would also want unique, yet realistic tracks. Powerups wouldn't be too bad either.

I like to see an assortment of karts and bikes, or cars if your passion isn't Mario Kart. I also look for items that are very fun to use, like the Blue Homing Shell.

There are 3 good things I like to see in a racing game.
1. Good graphics
If the game is going to look crappy, I am not going to want to spend my time racing. I want my cars to look good.
2. Fast cars
Racing slow cars around a track is boring, I want fast paced action.
3. Good multiplayer
If a racing game doesn't have good multiplayer, it's not a good racing game.

Well when comparing what I like to see in racing games, the type of racing I like and  I'm more into is the type of racing offered in Midnight club L.A. As opposed to Need for speed. The features I look for in a racing game is more street like in Nature. I don't want a racing game like Need for Speed, No pedestrians or other cars, or racing on a closed coarse on a race track. The racing game features I'm looking for is the game must have other cars and pedestrians,  races don't take place on a closed coarse I want to race on a public street, full customization of the cars, a wide variety of car manufacturers makes and models.

To sum it all up in a list form-
*Full customization of the cars
*races to be on public streets and have racers weaving in and out and in between on going and on coming traffic (also pedestrians)
*Variety in car manufacturers(also official car manufactures ), makes and models