There are many sites that review iPad apps. For example: macrumors.com, appleinsider.com, tipb.com, tuaw.com
Zite and Flipboard for curated news and Zinio for my National Geographic subscription.
games – free Angry Birds and Cut the Rope variations
Talkatone to make and receive free calls over wifi using Google Voice.
usual ones – Skype, Netflix, Facebook, Dropbox, Box.net, Google, Bing, Koi Pond Lite, Pandora, TV Guide
For free TV shows/Movies – ABC, NBC, Crackle