I've been addicted to the the Tony Hawk Pro Skater games since Tony Hawk Underground (I think it was the Story Mode that really made the game click for me) (and I've since gone back and played all the earlier ones). I usually play the games exclusively on the PS2 -- the games are dependent on fairly careful control fiddling and I just don't want to deal with a different controller. But I found a copy of Tony Hawk's American Sk8land for the DS at Toys R' Us for $10 and decided to give it a whirl.
I'm glad I did -- it was a thoroughly enjoyable version of the TH games. The DS seems to be providing PS1 level graphics and performance, which is fine for the skateboarding. It does make the skater and board customization kind of a waste - you can't really see your skater in enough detail for it to really matter. (And I don't think I'd like any lower level of graphics, though, so I'm glad I skipped all the GBA versions of the games.) I went through the whole story mode of the game and then actually went back and unlocked all the levels in classic mode, which is unusual for me.
The biggest place I noticed the cut-down nature of the game was the soundtrack -- there are only about 8 songs in the whole game and so they start to wear thin after a while. I Like Dirt by the Thunderlords is funny the first 20 times you hear it, but then...
Dan Telfer
I got the "Project 8" game, and it wasn't very good.