Most DirectX 9.0c games will run in Wine, with good results. Some newer games will run as well if the engine is coded to run in Wine (note: A couple of game engines are). A big problem with Linux gaming, is the latency of the Linux Kernel (Valve is making a huge mistake by making the Steambox use Debian). This is why both this generation of Playstation consoles and the previous one run BSD based operating systems.
You may want to check out Racer. The graphics are nice, and there are many 3. party cars to download. With that being said, it's been in development for at least ten years, and every release is incomplete and WIP-ish. So far, there's no proper AI, and the physics is patchy.
_________________
“He who controls the spice controls the universe.”