Asking for advice before installing Win 7

I have been running FS9 FSX and other games om a AMD X2 6000 system with Win 7 RC 64. Later in the week I await my purchased Win 7 Prem 64 and everything will be reinstalled from scratch. On a second computer running Win XP Home I run WideFS ASA FSBuild. I would like to hear advice on what to think about during the reinstall. For example I have both FS in their default install locations which has been pointed out to be less god. But do I need to reinstall programs on the client XP machine? More to think about? Special options or settings that should be avoided or used?