Probably the best racing game on the Xbox from what I have played, but not the best overall...
Not Recommend---Anyone who really prefers more cars than more tracks.
Project Gotham Racing was a launch title for the Xbox, and is an excellent racing game. It is probably one of the best racing games I have ever played, but it just doesn't contain all the content and depth that other racing games have. Games like Burnout or F-Zero rely on arcade style movements and speed, while games like Gran Turismo and Forza Motorsport rely on simulation. Project Gotham Racing is in between both of those, and therefore has qualities of both. Racing is still very fun and not very life-like as in simulation games, but it doesn't have the fun of speeding around ridiculous curves and stuff like that. There are a lot of tracks in this game (over 200 I believe), but not many cars. I myself would prefer more tracks over cars, so this game is really cool in that aspect. Even though there are a lot of tracks, though, their designs are mostly the same. They all look different and great, but in reality they're just squares with SOME different turns and areas. The graphics are ok, pretty good for the time this game came out. There is anything special with the sound, either, it's just decent. One thing this game does have, though, is a lot of replay value. Even if you only have a few minutes on your hand, you can easily just snap right into a quick race and have a blast doing it. The Kudos system is really fun, too, which provides you with points for doing things like speeding, getting a lot of air, and drifting (which is nailed perfectly in this game, unlike others). Multiplayer is fun, too.
Conclusion---If I were to buy a racing game, I would probably buy a Burnout game or Need for Speed, but Project Gotham Racing wouldn't be too far down on that list. If you already have a bunch of driving games, you should definitely add this game to your collection.