I've been running Windows 7 at home for a while now, and have been very pleased with it - on a decent spec machine (Quad core, 4Gb RAM, lots of SATA-II disk etc), it absolutely flies. As did Vista before it, if truth be told.
When I got this machine, I had it set up to dual boot between Windows Vista x64 and XP Media Center, partly because I had some software that didn't like Vista. One of the problem software/hardware combos was an oldish Canon 5000F scanner that gets used once every few months or so, but didn't have 64-bit drivers available. It wasn't enough hassle to make me want to go & buy a new scanner.
On moving to Windows 7, I've just used the Virtual Windows XP, or "XP Mode" (which has now RTMed - available soon), function, which lets me run an XP virtual machine that has access to local resources like hard disks etc.
After firing up the Virtual XP instance, the scanner is listed under USB devices - the software was easy to install since the hard disks of the host machine are visible to the VM, and it was a snap to configure the Canon scanner software to save its output back into the Documents library of the host.
So all in all, a bit more trouble than if it just worked natively - but the XP Mode offers a solution to the gnarly problem of old hardware that isn't being supported any more by its manufacturer. It certainly saved me the £50 or whatever it would take to buy a new scanner!