I am really liking the improved window management in Windows 7. Drag a window's taskbar to the top of the screen or Winkey+Up to maximize it, to the left or right or Winkey+Left or Right to resize it to take up that half of the screen, or Winkey+Down to minimize it. It's great for dual monitors or high resolutions. Speaking of dual monitors, historically, if you wanted to move a maximized window from one monitor to another, you've had to unmaximize (OK, "restore") the window, then move it over, then maximize it again. Now you can just drag the title bar of a maximized window from one monitor to the next and it'll automatically maximize.
The new taskbar is pretty nice, although I have a few usability gripes with it. If an application has multiple windows open, the timer for opening the window list upon hovering over the taskbar item is way too long and results in a slower experience than the traditional taskbar. On the other hand, it can fit a whole lot more. The improved notification area is also nice - I can finally configure how I want individual status icons to be displayed.
The Start menu (sorry, Windows menu) is largely the same as Vista's, which was an improvement over XP's, which was in turn an improvement over the Windows 95-style Start menu of everything before it.
Some improvements have been made to Alt+Tab, namely, if you hit Alt+Tab and leave Alt held down to leave the window list open, you can now click on one of the windows to jump to it instead of having to Tab cycle through to it (handy when you have many windows open at once).
It just feels generally faster than Vista - they've tightened up UI timings and they also reworked the Aero backend so it takes less memory.
Overall, I like it well enough to have replaced XP on my workstation with it. I'm also running it on my gaming machine (which was built with the idea of running Windows 7) and my laptop (because certain things about Ubuntu were just ticking me off). However, I wouldn't say I liked it well enough to pay $100+ for the upgrade - $40 for students should be the regular price, and there should be no "Home" edition. As Jeff Atwood
points out, lower pricing can actually cause a large enough increase in sales to result in more revenue, not just equal. Now if only the multimillion-dollar marketing monkeys at Microsoft (yeah, try saying that three times fast) could figure that out...
--- Mr. DOS
P.S. The funny thing? Gnome's had a significant portion of this stuff for years.