I run the same setup. The only problem i've encountered has been updates to Office 2007 messing around with an Office 2000 setting
that required repairing the Office 2000 installation via the Control Panel. Note too that Outlook 2000 isn't fully compatible with
Vista, but there are workarounds - see http://www.outlook-tips.net/howto/vista.htm. Even so, Windows Mail (which comes with Vista)
is more secure than Outlook 2000 and includes anti-spam filtering. Vista's Mail and Calendar programs are likewise viable
replacements for the equivalent functions in Outlook 2000.
[MVP - Microsoft Word]