Still had a couple lingering problems from a mostly resolved software conflict I had, so I transferred what stuff I hadn't backed up yet to the external and decided to give win7 a try before the rest of the parts arrive for the retool.
using the ms usb tool was pretty easy, not very fast but didn't take much action on my part. found out after install the iso was sp1 so had very few post install updates waiting.
only minor hiccup I came across was that in the boot select with the usb drive in, I selected removable devices the first couple of times, and when not finding one it rebooted. when I decided to look through other options I saw the usb under HDDs and installed from there.
at least now I can spend a couple days trying to figure out all the personal choice options as I had my vista looking mostly like XP and wouldn't mind keeping the feel.