In addition to a new UI, that is supposed to be slick and cleaner, iTunes 11 is said to feature closer iTunes integration. Instead of the iTunes Store being a web browser (like what it is now), the new iTunes Store will be integrated into the entire app, like what Spotify is currently. Since iCloud will be integrated into iTunes, the program will function similar to how Dropbox works – files that are backed up onto the cloud will be automatically downloaded onto your computer, giving you a hassle-free way to backup and transfer files wirelessly. Even app data will be synced to iCloud and with your iTunes library.
No word when iTunes 11 will be released, but it’ll probably be at the same time as iOS 5, and hopefully the next iPhone as well. Stay tuned for more details.