I too have felt very at home with XP, but now that I've go Windows 7 64bit I can't go back. The interface just rocks. I love how the GUI works now, and the speed alone is worth the price of admission. My computer takes about 45 seconds from power on to entering Windows, and that's with the boot priority still set to CD and having to type in a password. My machine feels so much faster being able to finally harness 64 bit processing power and drivers, as well as my 4 gigs of Ram the XP 32 wouldn't read.
I wasn't too keen on the thought of having to do 2 installs, but from what I understand talking with others, you clean install with the upgrade disk, and just verify your preexisting copy of Windows by entering the old serial. Vista users can upgrade without losing their files and stuff, but XP owners will end up with a clean install...not a problem for me since I like clean installs.
As for HP...my 2175 All-in-one doesn't have Windows 7 drivers, but Windows installed generic printer drivers, all I had to do was plug it in and it took all of 30 seconds...which is so much better than the normal, tedious printer installations.