Today at the Alpharetta office, some of our team is getting together for a Vista and Office 12 loadfest. There will be about 20 of us in a room watching geek movies and installing the latest bits.
I installed Office 12 on Windows XP about a week ago, and no problems so far. Confidence is pretty high on that one.
I ran the Windows Vista Upgrade Advisor on my machine, and it reports that everything should be fine with my Toshiba Tecra M4. The parts I am most nervous about are the experience (speed and perf) with Virtual PC (since I still do a lot of Team System demos using VirtualPC) and whether one of the hotfixes for VirtualPC on Centrino will still work.
I will blog an update later to say how it seems like things are running.