Something on my "to do" list that is long overdue is to put together some first aid kits; one for the car and one for the house. My Xterra comes with one that's pretty nice, and I've even added a couple of things.
If you're shopping for things to put in one, or are trying to start from scratch, go on over to Hell in a Handbasket for some ideas. Also, check out the comments section for some reader weigh in. Excellent ideas in there!