Easier and simplified iTunes Store browsing and navigation
Previews of any song, TV show, album, or movie from the Apple Store
iTunes LP, which allows you to download a digital version of specific albums with animations, videos, and other visual items.
iTunes Extras: It essentially turns movie downloads into true DVDs, with the video commentary, cast interviews, and photo galleries in-tacty
Genius Mixes: It turns your playlists into something akin to a radio station. It knows what songs just go together.
More detailed and improved syncing
App management: Yes, you can finally manage your iPhoneapps in a clean way. This is something you all have been dying for.
Integration with Facebook and Twitter