Well, variable files hold your styles, paths, etc, so those are important. It looks like the vars_*.* are those files.
Aside from that, you didnt say anything about your server, but I prefer to telnet in and zip up the whole board once a day so I save everything. This used to suck as my zips were like 160 megs , but now they are 5-10 megs <img src="https://www.ubbcentral.com/boards/images/graemlins/smile.gif" alt="" /> I keep my board all in one directory as well, so thats easier to zip too.
