My favorite game for the iPod Touch is Bejeweled 2.
The third-party app I use the most is Shopper.
Handy Level is cool and free, and it would be useful in setting up saddle and handlebars, too!
Does anyone else find it weird that the iTunes interface for iPod Touch/iPhone is so stripped down? It doesn't even have a progress bar showing how much more of the song is left, or allowing you to rewind. No lyrics. No info pages.
I'm about ready to see if there's a third party music player like Pocket Tunes (probably not, they wouldn't allow it in the App Store I don't suppose) and that's just goofy!