for just around town I carry a flashlight, needle nose pliers, spare fuses, flashlight, jumper cables, chain, code scanner, and a big roll of some heavy duty tape that I need to replenish, most of these items have been more useful in helping others out instead of myself, for longer trips I either throw a whole tool bag in the back or the basics 7,8, 10, 13, 15mm, channel locks, vise grip, ratchet and breaker bar, and at least a couple gallons of water. most of that stuff will fit in the jack storage compartment and/or center console.
a package of zip ties and bailing wire are probably good to have also
ya never know....