A lot of time has been spent discussing the new interface that's come by default with Gnome 3. Plenty of people aren't very keen on it, thinking it's a bad idea to try and create a single interface that scales on mobile devices, touch screens and traditional desktops; they also think it's a bad idea because it breaks lots of familiar habits and forces users to re-learn how to use their computer.
I've always been partial to the Windows Phone 7 interface, and I can't help but be impressed by this latest offering from Microsoft. It's information dense, apparently quite usable and visually striking. Whether or not it works in practice or not I don't know since it doesn't work with Linux (and is obviously non-free).
Make of this what you will, but I think this suggests that the Gnome team has not only been ahead of the curve when it comes to the direction they've taken the new interface (Apple are also reportedly integrating elements of iOS into their next desktop OS, Lion), they've also been relatively conservative in their implementation.