Coming from a completely computer illiterate person married to a computer nerd, not sure how much good my comments will do, but here you go!
My new laptop has Windows Vista. I didn't want it because I'm a creature of habit, but so far, it's working fine. It's ugly, I don't like the aesthetics of it, but functionally is fine. They rearranged some of the old, familiar things of Windows (basic things, like the way you change your desktop) which I am not happy with. Also, mine came with the new office suite, not sure what it's called, but I don't like that, either. Told you I'm a creature of habit! All the top bars and commands are different, and I could use the old ones in my sleep, so that's a HUGE pain. Plus, they are WAY slow (just Office, not Vista).
So really, I have found some annoyances, but I would be willing to get it again. If I had a choice- all the same specs but with XP instead of Vista- I'd probably get XP just because it's not so ugly. But, since you can't get a computer that is as "fancy", or high performance with XP now as you can Vista (so says hubby, but I don't know what he's basing that on), I would buy Vista again.
Now, from hubby's end, he likes Vista. He didn't when it first came out because it was buggy, but now adores it. His company (computer company) gave out some fancy version of Vista as a prize for something, and he fought hard and won it and was SO thrilled!
Hope you enjoy your new computer when you get it, no matter what system you use on it!
PS- I LOVE your butterfly-chasing kitty signature!!