Kotaku: "There were two main reasons Microsoft decided to totally redo the Xbox 360 interface: 1) to make everything easier to find and 2) making it easier for the Xbox team to make changes to the system on the fly (instead of having to wait for semi-annual updates).
After spending a little hands on time with NXE, I'm pretty convinced they've succeeded with that first goal (time will tell with the second). A whole slew of navigation options make it easier to locate anything from a recently downloaded demo to a group of friends playing Call of Duty 4 that you can party with. The Spotlight channel highlights whatever's new in any channel (movie trailers, content packs, demos, etc.) and the actual game library (gasp!) has a details page that will display all the stuff you've downloaded for it. You can even see stuff you haven't downloaded, like if there's a new map pack, and jump from the detail page directly to Marketplace to buy the content."