Oner of the key features I have always missed in Windows are virtual desktops. Virtual desktops allows you to have several desktops open at once, each with their own programs running.
I'm the kind of person who need order on my desktop. I can't work if I have 10 overlapping windows in front of me. Under Linux and Unix I always create 4 or more virtual desktops, so that I edit code in one, read mail and do instant messaging in an other, edit graphics in a third one, do remote shells in a fourth and so on. Under Windows it has always just been a mess.
When I installed Vista Ultimate, I kindof expected virtual desktops. But no - Windows was just as dull as always. But I found an Open Source project that implement virtual desktops for Vista! That's cool. I mean - thats /really/ cool!
I am now using Vista with 9 virtual desktops - one for each of the numpad-keys. I switc between them by pressing the Windows + keypad key for the desktop I need. Email is 2. Code-editor is 6. Gimp is 9.
Thanks to this program, I'm starting to actually /like/ Vista ;)