One of the small issues I faced while switching my development machine to windows 7 was a bug/exception in an application I was working on in parsing date format.
After switching my regional settings to the “expected” format, I still got the same exception. After playing a little with the regional settings, I realized that I was switching only my account date format, not the whole machine's date format. To push those settings to other system accounts (like ASPNET, etc), I did the following steps:
After setting your your account regional settings, switch to “Administrative” tab:
From “Welcome screen and new user accounts”, click “Copy setting”: