As far as upgrades go, I used to avoid them like the plague because they really did cause friends a lot of grief. But I have gone through almost all of the builds of Win 7, started with 32 bit. When I switched to 64 bit I, of course, did a clean install, but it has been upgrades since then. I had one 32 bit upgrade fail on me, probably because of an early version of AVG still being installed, but Win 7 rolled back perfectly. I really think MS has done a great job with the upgrade process. Clean installs will always be better, but with my insane desire to try every new build I just don't have the time.