Shazam will work with the Touch if you use the mic on a pair of iPhone compatible headphones. In fact, if you haven’t already done so, I suggest you invest in a pair of Denon ‘phones that are iPhone compatible; can’t remember the model, something like AH-C225 but they’re around £50 and give you the remote as well. Sennheiser ones are pretty good too, but the Denon’s are cheaper and as good.
Starwalk’s a good app, you can get it to locate your position without GPS, and it’s just lovely. Living Earth HD is also very nice as well.
Oh, just remembered, the various ebook readers are a must, Stanza, Kindle and iBooks. It’s worth having all three because books are covered by regional copyright, so an author’s complete works may be split across several sources. It’s impossible to get all of William Gibson or Neil Stevenson’s books from one store, my Gibson library’s spread across three readers because of copyright and such like.