What to save before I format my mac?

Safari Bookmarks (or firefox)
iTunes library (entire library, not just music)
Mail if you want (I usually just let them get deleted, there are backups on the mobileme server anyway (if you have mobileme)
iCal events
Pictures/iPhoto library
Documents/Files

If you like, also
MSN, AIM, iChat, Yahoo, or Adium chat logs (or any other messenger)


If you use programs like Netnewswire, or keyboard maestro, a backup of the macros, or RSS feeds would also be wise.

that should pretty much cover things. There are also other things like iDVD, GarageBand, iWeb, and other programs you may have projects in that you may wish to save.



Hope I didn't miss anything lol

 

Don't worry about backing up specefic things. Just plug in an external drive and do a complete backup with time machine.