Well, I'm running Windows 7 on a couple of netbooks that have 1.6 or 1.66 32-bit "Atom" processors and 2Gb of memory. They're not half-bad, and better than they were on XP.

The windows 7 "experience" index is fairly low, but again, subjectively I find them to be fine. And that's running the fancy desktop features as well. One of them is running quite a few things in the way of services, as it's being used as a "mini" web dev environment for PHP and ColdFusion along with MySQL.