Microsoft lured me into upgrading my laptop to Vista Ultimate with a free copy of the OS I got at a Launch (2008) event. So, last night I bit the bullet. I'll try to make notes here of things as I run into them.
1. The upgrade took hours. I hear clean installs are much faster, but I wanted to keep a lot of software I already had installed.
2. Desktop Icons were BIG - solution: click on desktop, hold Ctrl, and use mousewheel to resize them.
3. Windows Search wants to index my whole hard drive - serious disk usage - solution: disable Windows Search service
4. Aero works great - but if you want the diagonal window task switcher, you have to learn to use the Windows-Tab instead of Alt-Tab
5. AVG Anti-virus had to be reinstalled. I have the free version, but the license data didn't carry over in the migration.
Will post other stuff as it happens/I remember.