One of my most-used apps on the iPhone is actually the App Store app itself -- I download lots and lots of different apps for review, and I constantly need to search around and find information on apps for posts. So I'm excited to see that all three of Apple's major content stores on iOS have been updated for iOS 6: iTunes' music and movies store, the App Store itself, and even the iBookstore have all been updated for the new OS.
The most obvious change at first will likely be the slight color change: The top and bottom bars in each store are now a darker gray. And there is more information listed more clearly in each store. In the App Store app, each app now shows a screenshot along with the price and title, and you swipe from left to right to browse through the apps in search, rather than just seeing a big list. iTunes looks different as well, and you can now buy apps and content without getting kicked out of the app completely.
These changes are all fairly small -- mostly just simple UI tweaks or ease-of-use updates. But they should make buying and finding content on these stores easier, especially for those of us who end up using them often.