For Win XP I had to download a kit from MS that would install a function called Robocopy, then create a batch file that would run the command. Basically it would backup all the files that I wanted then each night would automatically run and only update files that were added or updated.
I haven't checked yet to see if Win 7 has that same command in it, but I think it could be handy, because you could just create the batch file (just a file created in notepad and renamed with the extension .bat) then set your scheduler to run the file every week, or every night and it would be very quick.
The only thing is, though is that you would need to know the paths that all of your files are saved in.
I haven't tried the Win 7 backup system yet, but that is only becuase I have 2 computers with 5 HD's, so I tend to keep copies of my stuff on the other comp.