Thought it might help to add my experience of Win 7.
Upgraded from Vista home premium to W7 home premium with a downloaded copy.
Went on no problems and nearly all the programmes worked. However - the scanner did not work (HP 3010) and I had to talk to HP to get a solution. Win 7 comes with IE 8 built in. This has a glitch (for me) that does not allow opening a link, say from a pprune thread. Have tried many suggestions from Google but no go.
Opera and Firefox all OK.
Another problem. I downloaded Chrome. Then uninstalled it! It left another glitch that prevented me from opening a link from any of the office 2007 applications. Googling found me a solution to that problem.
It still looks like Vista though
MC