Well, on my system it says I will only need some new drivers (Vista compatible) for some of my hardware like USB tablet (drawing pad), my Canon Pixma IP3000 printer, and my Lexmark scanner. I am sure some of those drivers are already available for download if not all... other than that, my desktop is ready for a "big switch". Besides, I already tested one of those Vista beta versions, and it worked fine, even all AERO bells and whistles. Of course, excluding all those little bugs that are common thing when it comes to beta releases...
Cheers !