If you're in to watching TV and would like a really nice TV Guide type app I would recommend "What's On?". It allows you to store your favorite shows and see whenever they are on within having to search through any of the listings. It's a great app and it's either $0.99 or $1.99 in the App Store.
Tweetie (if you Twitter)
Photogene (best photo editor)
Orblive (if you're a PC user and want to stream media/TV to your phone)
Ocarina (amazing wind instrument)
Air Sharing (easy file transfer and viewing without iTunes conversion/sync)
that's what I thought asswell but I got a 50$ iTunes gift card and I bought super monkey ball and it charged to my credit card so I called Apple and sure enough they said iTunes gift cards work with everything in the store exept apps.