Don't forget that Dirt2, like Street Fighter or Dawn of War 2 etc, are all Windows Live games.
So not only do you need to backup the Dirt folder, but also your Windows Live folder and, well, loads of others.
A complete pain in the buttocks. Why wont companies learn that we want a single folder with our save in that we can cut and paste as needed? Rather than four or five folders, some of which you'll almost never find, and even then it doesn't like pasting back in.
If only Microsoft had included a "My Games" folder in the MyDocs, then games could use that...