I've been running Windows Vista Ultimate at home for several months now. Overall I've been satisfied, but I only use my home PC for a handful of hours per week, and I don't get to do much development from home.
We have been using my Lexmark X5150 to scan and print, and that's been going okay under Vista, even though we can't use the Lexmark software for scanning. A few weeks ago though, Windows Photo Gallery stopped scanning for us. We kept getting the error message, "a problem prevented the document from being scanned." By wife tried several things and couldn't get it to work--same error every time; reboots, automatic updates, but to no avail.
For grins and giggles, I decided to choose "Run as administrator" for Windows Photo Gallery. Sure enough, it worked like a charm, first try, no errors. Close everything down, run it again under normal privileges, still no error. Strange! I'll have to remember this for other bizarre errors under Vista.