I was running Windows Server 2003 on my home machine. It's a bit dated with a 3ghz P4, 2GB DDR400, 6800 GT, etc...
I had automatic updats turned off and needed to install Visual Studio .net 2005 for a project I wanted to work on at home. Well I tried to install 70 critical updates and then .net SP1, and my machine pretty much crapped out.
I backed up everything and was going to just install XP and get just VS.net 2005, SQL Server 2005, Photoshop, and office running. Well XP and Server 2003 would not install.
I had a version of Longhorn server sitting around and installed that. It ran, but was still to buggy. I jumped on MSDN and grabbed Vista Ultimate and installed that.
To my shock the install went great, VS.net 2005 w/ SP1, and SQL Server with SP installed just fine. Office 2007 and photoshop, etc... also installed fine. No problems or crashes or anything. A first for a new Windows install.
Turned on Remote Desktop which works just fine. Played around with the built in AV program, which looked stout. The security is annoying at first, but it really looks like it's vastly improved.
Even with my older system, Vista works just fine. If I didn't have too much running on my new XPS at work, I'd put Vista on it as well. I just have too many Visual Studio 2003 projects I need to support, which can't be moved to 2005... so until those projects are dead, I'll have to keep running XP at work.
My user experience is a 4.2 (guessing out of 10), but everything seems to be running just fine