Well I have to tell you one thing. I went in to Vista expecting half my crap not to work, and I kid you not, everything installed perfectly (except my on board wifi software grr.)
On some driver installs it will let you know that these drivers haven't been approved, and if you want to install anyway. Anyway my sound card is a pretty old soundblaster and it installed perfectly.
But yea, it isn't like the upgrade XP was. XP was their finest home OS, using the very stable Win 2000 kernel it brought stability and made the blue screen of death something of the past. For me Win 95 was the biggest jump from 3.1 and then XP was the biggest jump after.
After you install Vista and turn on Aero you just stare at your screen in amazement. After that wears off you realize it is very intuitive, well organized, and superb in terms of finding you updates for anything you have. I also found my download speeds to be faster (for some reason) in Vista.
The only issue is that if I am going to legally purchase it, I will want the Ultimate Ed. which is $400. That needs to drop by 50% before I even consider a legal purchase.
My current copy of XP is from the magic underworld store, because my legal copy was activated far too many times... bah.
So I found a...err...software... for Vista that just stops the 30 day grace period from ticking. Dual booting is fine as well.
My biggest worry was that they would force us to put up with the Live feature for gaming. However while M$ games will force that feature, Epic, Valve and others have denied that their DX10 games will use that feature.
In the end, Vista Ultimate is rather nice, just not $400 nice. The OEM is half the price, but I don't want to be restricted since I change hardware often.