Here's a few I can think of.
By the way... You're supposed to get Amazon MP3 credits with some of the paid ones. If you don't see an e-mail pop up after you buy them, ask customer support and they'll credit it to you.
- Epicurious Recipes & Shopping List
- TuneIn Radio (there's a free version)
- IMDB (I think it comes with it pre-loaded still, but if not then that)
- BeWeather (nicest weather app you can get - make sure it's the Kindle version)
- Ambiance (it's a relaxation sounds app, they make it for every platform, love it)
- ES File Explorer (we all use this here, comes in handy when you download something, or want to organize files)
- 500px (great place to look at amazing, magazine/museum type photography)