Need for Speed Underground is fun for a while, but then it gets boring.
The graphics are good, nothing special, just good. There are rarely any frame rate isues, it just doesn't look that good.
The story is pretty simple, just race, get new cars, do 'em up, and beat the best racer in the city. There are no cops or anything to worry about here. Just look out for oncoming traffic.
The sound is pretty good. The cars all have different sounds, the traffic toots their horns at you, usual car stuff.
All up, this game is probably only good for renting. Maybe buy it if you like the rest of the need for speed series.