Thanks for the great suggestions everyone. To follow up, here's what I did as a result of this thread:

-Put batteries back in my smoke detector

-Backed up all of my data (hadn't done this for many months)

-Got a small swiss army knife and put it on my keychain (already been useful)

-Looked at a few fire extinguishers to make sure I knew how to use them

-Put some useful things in my messenger bag (kleenex, pencil and paper) - I'll probably try to keep adding things to my bag as I think of them, since I almost always have it with me

All of the car-related suggestions seemed like good ones, but weren't applicable since I don't own a car. Some other suggestions were good but required more time than I was willing to put in right now, or weren't applicable for other reasons.