Only the saves folder is really needed, but the other stuff doesn't hurt I guess

Backup your saves folder, you don't need anything else. Of course if you've made heavy tweaking to your pref.ini and don't want to lose that "just right" look that you finally got then you can back that up as well. But then again if you had done that tweaking you wouldn't be asking this question...
ok thanks to both of you

i didn't tweak anything, so i just need to back up the saves folder, nice!
you can lock this, Freddo! (nice nick, it means cold in italian, i guess you know)