I look at BOBs, survival, and neccesitty bags differently but all three will have many common items. Like said above there are a lot of great sights out there to get you started in the right direction. Make sure you don't overlook meds (doctor given) and don't laugh--tooth paste and a tooth brush.
Nothing to laugh about regarding tooth paste and brush. They are important
to have with you <img src="/ubbthreads/images/graemlins/thumbup.gif" alt="" /> as is a decent first aid kit.
Cheers