As a general rule of thumb I usually rename all .conf files I need to change by adding a .original to the end. I can then in a worst case scenario do a
sudo find / -name .original
I can then backup those files to another location and drop them in on a new box if I need to reformat or create a new image.
I will usually have to "install" the other apps, but at least the configs can get placed in quick and I'm up an running. I realize that it's probably a little late for you now, but may help in the future. I do this for a simple reason. It takes very little drive space for a backup of a fully configured system.
As far as personal information and documents you simply backup /home every now and then, or create it on it's own partition on the hard drive and never format it on a fresh install. If you do that you'll never have to worry about backups while upgrading your distro, although you're still screwed if the h/w fails.
If you're looking for a snapshot pick up a drive image solution like Ghost or something.