GT3 is quite fun, though I find myself playing SSX and lately SSX Tricky more. All 3 of these games also support widescreen, more fun on the HD set with the wider view of the courses. I've seen SSX for $25 because the sequel Tricky came out.

Both SSX games make a great use of audio - the sound track adjusts to your current ranking- upbeat and full of energy when your doing well, not quite so upbeat when your in last place. Gameplay is great. The courses in Tricky are mostly revamped versions of the courses in SSX, though there are some new ones. They're changed enough that knowing the course layout in SSX can trip you up in Tricky - ie left turns become right and vise versa. Tricky has a lot of slick behind-the-scenes extras, such as the voice actors, course creation, and so on.

I recently picked up Klonoa2. It's a 2D platform game set in a 3D world. You can basically go left/right with some up/down. The 2D course weaves around the 3D world so you can often see other parts of the 2D track in the background - neat effect. As an added wrinkle, you sometimes have to fire into the screen to clear obsticles on a future point of the world. The game has anime-like in characters and the visuals are well done(I loved the sections with hundreds of "fire flies" floating in the air).