No, that's a common misconception (yet more people who think they know Vista but don't!).
Aero itself is not just the fancy UI. It's also a GPU-accelerated backend. It takes the load of rendering windows off of the CPU. This means that when your CPU is being raped, Windows will remain far more responsive. It also fixes numerous mulit-monitor issues with spanning, and allows the fancy UI without any real performance loss.
XP does something similar with Error Reports. You can turn both off.
XP is the same way? Vista is actually better about killing programs than XP was, especially when you're trying to reboot the system. If you hit reboot, it'll prompt you to kill any programs that aren't quitting normally, and if you don't respond in about 10-15 seconds, it'll go ahead and kill them for you.
XP does this too, and you can turn it off if you really want. Vista actually improved thumbnailing performance over XP though.
Yes, but unlike XP, all of your system tray icons will return. Everything resets itself when explorer comes back up.
Unzipping on XP was also terribly slow. File copy performance WAS fixed with a few hotfixes, and really only bothered network copying. I typically max out my hard drive/network when copying.
Many parts of the interface were changed for the better, and on the off chance you can't figure out how to get what you need, just search for it. That was the entire purpose of adding search boxes all over.
For example, someone was complaining about the number of clicks it takes to get to network connections. I can do this just by going to control panel, and searching for "view network" and hitting "View Network Connections".
XP does the same thing by default.
This is wrong. If you have a powerful enough system, the gaming performance will become negligible. And if you're running DirectX 10, you may even see a performance improvement at high quality settings. (See Anandtech's latest article about FarCry2)