According to an article on the Macworld website, iOS 5 has a couple features that are available but not enabled: 1) a panoramic photo feature and 2) an alternate way of invoking spelling suggestions. Interestingly, you can enable these features without jailbreaking your device. But you do have to tweak it a bit — so this is probably only of interest to the techies among you. Also, the features are pretty fritzy, which is possibly why they weren't enabled.