I currently have the Pioneer 3350BT in the car and im loving it. It seems to check all your needs 'mp3, DVDs, divx , iPhone compatibility, USB compatibility , Bluetooth etc however the screen is only 5.8inches which may be the downside.
Before getting my headunit i tried researching about it and finding reviews and i reckon this youtube video best shows what its capable of. (The title of the video says its a Pioneer 3300BT, however mine is a Pioneer 3350BT and it looks and functions exactly the same)

http://www.youtube.com/watch?v=W-DUB...gf5HQ&index=10