If your version of Office wasn't supported, would that upset you? Do you
think others would be upset if their version of office they were using
wasn't supported? There are millions of users of office, and Microsoft
wouldn't leave them unsupported, would they?
I have run Office 2000 on Windows XP and Windows Server 2003. Microsoft
provides service packs to update Office 2000 (and other versions). If there
was a problem with running on Vista, I imagine they would provide a service
pack when Vista becomes available.
Here is a snippet from Paul Thurrott's review on application compatibility
with Beta 2
http://www.winsupersite.com/reviews/winvista_beta2_04.asp
"Microsoft Office 2003/2007 (and OneNote, FrontPage 2003/SharePoint Web
Designer 2007)
Works: Yes
Notes: Both Office 2003 and 2007 install and work normally in Windows Vista
Beta 2. Starting with Office 2007 Beta 2, the Aero glass effects work
properly as well."