The new taskbar is a lot nicer. I usually have a crap load of stuff open like 3DSMax, Photoshop, Source SDK, and Hammer, as well as Firefox and WMP. On XP/Vista this would usually take up the whole taskbar and new windows would be squished in. Under Windows 7 this no longer happens as each window is represented by an icon on the taskbar leaving plenty of room for more programs.
Multiple windows are automatically grouped together which is nice. You can hover your mouse over the icon on the taskbar to get thumbnail previews of each window and hovering your mouse over a thumbnail shows that window in full. Very helpful for checking how a map is compiling in Hammer without activating the window, or checking on an IM convo.
Another feature is the ability to move windows to either side of the screen to be resized automatically so they take up half the width of your desktop. I find this useful when I have a web page I'm working on. I load up the page in Firefox and move it to take up the left half of the screen and I move Notepad++ to the right to take up the over half so they're side-by-side. Of course, this is something that can be done in XP by simply moving the windows next to each other but it just makes it easier.
Performance wise it's a lot better than XP. Logging in is very quick, all my start-up programs (AVG, ATi Catalyst, Razer Tray, Steam) are up and running 15-20 seconds after logging in, and games run perfectly fine.
All in all, I'm pretty goddamn impressed by it especially considering that it's a beta. I was a bit cynical at first as it seemed like a small leap over Vista but it's the little things that impress and because of this I'm definitely going to make the switch from XP. If you're on Vista though then you might want to check it out to see if it's worth it.
