Questions like this are in my humble opinion silly... of course you all will upgrade sooner or later. It's the only way this World goes... you have to keep up with the things around you.
Just remember all those silly stories about SP2 and how many people never even thought of upgrading to SP2. Silliest thing ever. Now, if anyone sees anyone not using SP2, first thing they advise him/her (especially in this forum) to upgrade to SP2 ASAP.
Also, what's unbelievable silly... now everybody adores Windos XP all of a sudden. I still remember all those stories about how "difficult" to use is XP and other things... simply, there is no Windows operating system as stable as Windows XP is... not to mention how easy is to troubleshoot your hardware/software/drivers problems, how much networking is simplified, and numberless other improvements.
I am sure many will still be afraid of Vista as usual when something new comes out... but I ask why ? We all need and want to learn more, and no one should be afraid of something new. Just remember how those stupid primitive people used to burn "witches" whenever and wherever someone brought something new. You had to stay stupid, or at least pretend to be stupid to blend into the crowd and stay alive. We are not living in the age of inquisition any more, so anyone is free to make up his mind best he/she can.
To answer that question... sure I will go with Vista as soon as it's gold and out. I had a chance to play with Vista Pre-Beta 1 and Pre-Beta2... still many issues, but that's why it's not public beta, it's something for developers and it's something that's still in deep development. All I can say right now, is that it looks and behaves promising and I simply can not wait until it's out.
Cheers !