Forza Motorsport has the best game play in any racing game I have ever played. It's definitely a must have for Xbox.

User Rating: 9.2 | Forza Motorsport XBOX
If you’ve been searching for a great, fun, long-lasting xbox game, you've just found the Holy Grail of Xbox. Even if you don't like racing games, this game will grow on you. Lets start with game play. The driving in this game is so simulated that it will make your brain hurt, but don't worry, there are plenty of options to customize to make this game just right for you. Want things slower? no problem, there are so many cars to choose from, you'll never own them all. Just keep and eye on how easy you keep it, because the easier it is, the less cash you'll get after each race. If you like it hard, you can select to have damage on, but the great thing is, it's not just cosmetic damage, but it's mechanical too! Hit a wall, your tires might lose alignment, or maybe your engine will start to smoke and you'll lose speed. You can also tune up, and customize (visual and performance) your car. Those are some of the defining factor of this such a great racing game. Next up : graphics. This game has great graphics. For the Xbox, maybe the best. Each track and car has great detail. Each tree or bush can be seen realistically reflected off of every curve or indent in your car. Even the trees are great. The sound on this game isn't an issue either. it isn't superb, but it certainly doesn't suck. Each car has it's own unique engine profile because every time you upgrade your car, its changes slightly and with every time you hit or knick a wall, it sounds different depending on where the car hits and what it hits. Talk about getting bang for your buck, this game is worth every penny.