Upgrade to Parallels 3.0 and Vista Business in what order?

I am currently running Windows XP Pro and Parallels build 3214. I want to upgrade my Win OS to Vista Business. Should I do that windows OS upgrade first, within Parallels build 3214 and then upgrade to Parallels 3.0?

Or vice versa?

I'm trying to figure out best practices here. I don't think anyone has posed this specific question. If it has been asked/answered, please point me to that specific thread.

Thanks very much.

 

If you upgrade to Vista first you will retain the option to retrograde from Parallels 3 to Parallels 2.5 - provided you keep a backup of your virtual machines. There is no path from vm's that start out in 3.0 back to 2.5.