I lost my main HDD last night also. about 1am-ish as I was getting ready to go to bed, BSOD. I keep all of my documents on a separate physical internal HDD (D:) and when I install Windows I just change the paths to the "My Documents" folder Etc.
I keep an image of Installed and configured Vista on an external USB drive, and do incremental updates every night automatically using Acronis True Image.
I also install Steam and all of the games on that drive, then all I need to do is install the Steam client to the directory and my games are there, configured.
It took about an hour to be back up and running, now I need to buy another HDD.