When I used Vista, it was always "Aw crap, I'll have to fix that."
With Windows 7 it's "Wow, that works great."
Just one example:
The installs (1st beta and 7068, both x64) recognized my dual video card/dual monitor set up (and not the sig rig below) and not only downloaded and installed the latest Nvidia WAQL drivers, but extended the desktop to both monitors on first boot. That would be twenty minutes of screwing around with XP or Vista.
As stated above, aside from the obvious technical and speed improvements, there is a much better "feel" to Windows 7.
I have had a XP/Vista dual boot installed, figuring I'd just naturally migrate over to Vista. Well, after a year it didn't happen. When the boot screen came up it was always "Why do I want to deal with all that crap? I'll just use XP again.".
Now, dual booting XP and Windows 7 it's "Oh boy, I get to use Windows 7 again!".
Pretty much, Windows 7 does everything Vista does, just better, faster, and nicer.
Only let down so far is no DreamScene on dual monitors.