Reinstalling windows 7 and ownership of user data on different drive

Hi,

I keep all my data on a separate drive. The last time I re-installed windows 7 I had to take ownership of all my data even though the user name on the old install and then new install was the same. After reading the forums I understood that the SID for my user name was different between the old and new installations.

So my questions are

1) Is there anyway to assign the old user SID to the user created in the newly reinstalled OS so that I don't have to take ownership for a huge number of files/folders recursively?
2) If there is no way to assign the SID how do people store their data to allow for easy reinstall of the OS/Migration to a different computer?

Thanks!