If you ask my honest opinion I hate
Vista to bits.
. The main reason is because it asks you so many questions when you trying to do something. As Rustic said, basic use and little use of Vista is fine however if you are heavy user like me you'll find it annoying, very annoying. It is so annoying that sometimes you'll feel to break your pc. Just one simple example, you want to run a spyware scanner, when you run it,
1: It asks you whether to run it or not (well duhh! I clicked on it to run it!).
2: It will scan the whole computer just to tell you that "at the end of this scan I will not take your spywares out because you didn't run the program using Admin permissions"
3: When you run it with Admin rights enabled, it will run the program slower, sluggish.
That was my story of Vista.
Now the part about what I like. I like XP because it is not that much annoying and it is in the market for so long that I know how to handle crashes and weird acts of it. I can even use shells to look like Vista if I want to.
So I ask a question why moving to an annoying system when you know you can mask your XP with Vista's skin. Mind you there are allot better skins out there then Vista's blackish skin.
Finally, you can do almost anything to XP to make and run like Vista. I'd rather wait till Windows 7 comes out and see if I can move to 7 instead of Vista.