I personally do have a B.O.B. in addition to an emergency kit in my car. The B.O.B. has basically everything I would need to survive for a while, minus food (I have a few power bars in there). Purification tablets, purification pump, survival knife, multi-tool, rope, flashlights, a survival mini-handbook, my backpacking first aid kit that also has a sewing kit and other stuff in it, etc etc.

I also keep an external hard drive in there that I back my computer up to. Basically if I have to run out of the house quickly (fire, flood, earthquake), it's the first think (and possibly only thing) I'll grab. I also carry it in my car if I'm going to be driving on desolate roads and might possibly have to walk a long distance.