The files you're referring to are the easy part. Like you say, just copy everything; it's 100% your files. I'm referring primarily to the stuff in appdata, which is what creates a challenge. Even after cleanup, on a good day my appdata contains 20,000 files in 6,000 folders, over 3 GB. 99% of that is flotsam that I don't want to back up, update, or wade through later, or tie up the backup program trying to keep up with it. For example, all of the crap in the browser cache is in there, and would be constantly growing in a backup. I created a surgical backup plan for that stuff, but it is still dozens of folders. That is where the chore comes in--doing that part manually.
BTW, badrobot, I just noticed that the image in your signature is animated. That's pretty cool! Hey, is there a way to "Like" a signature?