I forgot to mention an additional EDC on my keyring is a Res-q-me tool. http://www.resqme.com/what_is_resqme.html (no affiliation). I think there are a few other brands around if you look).

No matter if you are in a car, bus, train, or even in an office, its always nice to be able to safely break a window (in an emergency). There have been numerous situations especially in a buses and trains where exists are blocked or unreachable. So being able to make your own exit makes sense.

I've had the situation (once) where I was walking past a car accident. A lady was trapped in the car and the doors / windows would not function. Fortunately the rescue teams were only a few minutes away, but the ability to break that glass would have been very useful. Those hammer style rescue tools are not really suitable for me to carry on me, but the keyring tool is acceptable.

I guess most people on this forum realize that often our preperations will benefit the muggles in the community, rather that us needing them ourselves !