Originally Posted by Du-z
The way steam stores its files makes it rather dificult to do this as any games that use the source engine has alot of files referncing each other than arnt in a single folder (ie any other game will have ALL of its files stored inside its on folder within "common"). also the program back up certain registry entries, it would be next to impossible to seperate the entries from eachother without creating a lot of extra uneeded reg entries.
if you only want to restore a few games, you can just grab it from the "\bin\common\" directory of the backup root and place it in "\Steam\steamapps\common\"
you might have to "download" the game agian it will the HDD for the game and install it, it may download a few misc files but after that it will be fine and dandy.
there are other compromises that I might be able to work with but for now ive been rather buisy on other projects, if you are keen you could always look at it ;p.