Updated my iPhone to IOS 4 today! Love it! I was able to get my pages down from 8 to 2 using the new folder feature. Finding all my fav apps will be another matter. I'm sure there will be some adjusting to do with regard to the layout & organization.
Also, the new unified mailbox seems pretty cool, haven't had much time to play with it yet.
I also want to take a look at the iBooks app.
The 5x zoom on the camera is ok. Probably not a feature I'll use too much on this unit but perhaps on the new one I will since it has a better camera.