Just use a SVN system.
Its a good practice to use sourcecontrol for
your code and files. As you can also share it with other
users, and recreate your working environment anytime on
any PC.

Dont backup data that has no "value", meaning all
kind of Program installations, that can be redone anytime anyhow.

This simplest though is to buy a USB Stick, and copy your stuff
onto it before going to bed.