Jay Kimble has posted an analysis of the 100 reasons to move to Vista. Overall, he wasn't impressed. I have to say that I think that the following are cool features:

44. Ready boost - Gaving fast random access to cache is important, and it will certain reduce HD activity.
62. Windows Fetch - That one is a biggie. It means that Vista would learn that I usually have VS.Net, Outlook and FireFox open at all times, and will pre-load them to memory when the OS start, saving me time when I want to load them for the first time.
66. Shadow copy - There are already some stories about it saving a lot of time.
85. Switching encoding without rebooting - As someone that does speak more than one language, it is exremely annoying having to reboot to switch the default encoding. Furthermore, when trying to do i18n tests, I need to more back and forth fairly often, and that is certainly going to help.
96. Remote desktop improvements - Integrated Autentication is a killer feature for Remote Desktop.