I chose W7 Professional (64-bit despite my earlier comments about whether it was of benefit to me) as I reckoned I'd need IIS for various test web sites and for Windows XP Mode.
Before the move I browsed around to pick up any tips and found Windows Easy Transfer which I ran on my old system and saved it all to an external drive. As I don't keep most of my data on my C: drive and my whole system was anyway secured with Genie Timeline I intended to reformat the C: drive during the install.
The actual install was fairly straightforward though the path through the partition choice dialogues was slightly confusing, and the format option seemed only to do a quick format, I'd have preferred a full format. I got W7 up and running pretty quickly.
I had some issues with graphics and sound drivers but eventually seemed to have got it right. However I was getting various random BSODs (Driver Verifier and WhoCrashed pointed to a driver but not which one) so after 10 days I rebuilt it all last Friday. So far it seems much more stable.
Using Windows Easy Transfer to bring in my settings from the XP system was a real boon. All my cookies with, for example, forum logins, were there straight away. Full marks from me for a really useful utility.
Most software has gone on without problems. Some difficulty with Family Historian V2, Starry Night Pro V6 but got them both running. VB6 installed fine and my own VB6 programs installed and ran straight away. My DOS Basic programs run under XP Mode. Laplink Gold V12 works though always gives a warning message when started. My old Dreamweaver runs fine. MS Money V12 runs ok. My ancient Reminder program wouldn't run so I found this replacement. My HP Laserjet 1320 runs ok though there is no HP Toolbox for it so I can't monitor toner status. As I never use all my monthly broadband allowance I haven't installed Networx, my ISP provide a meter on their site that I can check once every day or so.
I didn't like the way Windows Explorer has removed features, e.g. status bar info, cut copy paste toolbar buttons but I found Classic Shell is an adequate substitute.
And the PC seems to be running faster, this may be 64-bit using things more effectively, it may just be the benefit of a fresh and clean Windows install. I haven't yet connected my XP Netbook but don't envisage any real problems.
After allowing a week or so to get used to the different look and feel I can honestly say that I like it.
Can't think of anything else at the moment that may, or may not, be of interest.