re: update
I had the advantage of installing Vista 64 on a machine that had already been "debugged" by somebody else for WinXP 64, so most of the driver problems were old news.
A lot of my old peripherals (video digitizer and a couple of others) are still on my Win64 32 bit machine. I've noticed that some of my old 32-bit programs like Photoshop and Acrobat are twitchy on the Vista 64 system, but if I spent money to update them to current versions, which are tested on Vista64, they would probably work just fine.
I was pleased to find a Vista64 driver for my old photoprinter.