Ah hah! The latest Vista CTP installed very cleanly. The first thing I noticed was that it took me minutes and minutes to figure out how to add files to Windows Media Player.
As I post this, I am surprised to see that the HTML-editing \<textarea> is not the WYSIWYG-style of IE6 on XP. The Games also don't work because they say they can't find a Direct3D Device to render to.
The Shell changes seem nice: the Search right in the Start, the thumbnails on ALT-TAB or hovering over the Taskbar.
I think I saw that programming for WinFX on this build might have some version issues, which is a bummer. I'm anxious to give Avalon / WPF a go.
But...handwriting recognition is available! Anyone with a cheap digitizer can now get a glimpse of the joy that is the Tablet PC!