I've been using the phone since about 10pm. And I mean like I have not put it down, except to type on the forums here. It was at about 90% after I activated/synced it. Right now it is at 78% and that is after games, movies, music, skype, a lot of safari, iBooks, iMovie, recording about 10 minutes of video, taking about 30 pictures, a lot of texting and facebooking, a 10 minute phone call (regular call over 3G), downloading 5 app updates over wifi, and the list goes on.
I couldn't be happier with the battery life right now. I never use my phone this much on an average work day, so I know I could probably get 2 or even 3 normal days out of it on one charge (if I had to). After 3.5 hours of pretty much non stop use I've dropped only about 12%. And my brightness is all the way up.