Well, as for me, from what I have seen of the new UI, I can only see 2 good features. Their "peek" feature might be somewhat useful, but I use alt-tab for everything anyways so it is kinda a moot point. Also, I like the drag to sides to snap the window to half the screen and drag to the top to snap to maximize. That could be a pretty useful UI change. As for that abomination they call the "improved taskbar"... All it is is a f*cking dock with a start menu and thumbnails, and I HATE docks! To me a dock is a stupid UI because it can't decide whether it wants to be a taskbar that lists open windows or a quicklaunch bar that shows icons for your launchers. I used to find the first useful (before i started using all alt-tab all the time), and the second I absolutely detest because it takes up valuable real estate that could be used for something useful like the taskbar. So, I think MS is making a HUGE mistake by going to a dock, even if they say it isn't a dock. The worst part is that there will be no option to even go back to the classic taskbar! Honestly, why do they feel they need to cram UI changes down our throats? I love Linux so much because it allows me to make the decisions on how my UI will work (for the most part) and I am not forced to use stupid docks and taskbars if I don't want to. In fact, all I use is just a system tray for the time and the systray icon for pidgin. Other than that, my interface is very clean and simple and it works just great for me.
Here's hoping that we can take whatever good things may come from win7 and watch MS shoot itself in the foot again with the bad stuff!
-Zorak