have always carried a schrade LB7 in the truck jockey box & recently added a $20 gerber big rock camp knife in case the bigger fixed blade was necessary...
after reading through this thread though i'm thinking my lmf II would be handy in there for glass breaking, & a multi-tool would be a good addition as well... i currently don't have a multi-tool though, lost my gerber multi-tool to tsa many years ago & until recently haven't thought about replacing it, however having trouble deciding on which one is best, will have to do more research here to finally figure it out!