MY parents recently got a new computer with it. Spent abotu an hour mucking around with no troubles to speak of. That said, I ddint like the feel of it. Items seemed out of place, and doing basic navigatiosn and tweaks that I do with new installs were difficult to figure out. I'd stick with XP for now.
XP can run on a slower machine and is overall less demanding.
If you want a computer for gaming, many new games will only run with Vista.