Useful skills and knowledge, part 6.

Parkour:
Great for urban areas.  You won't want to be in a city during the apocalypse, but if you have to gather supplies or find people in the concrete jungle, free running and a crowbar will get you almost anywhere.  It doesn't take much practice, and you'll get athletic training as a bonus.  Overall, this skill is very useful--although I wouldn't say it's vital.

Medical training:
I've already indirectly covered this in the "basic survival skills" skill group, but medical training is important enough to mention twice.  Sometime during any disaster, you will get hurt.  Maybe not much--scrapes, bruises, even just sunburn--but for any serious injuries, you'll have to know how to treat and move people without hurting them.  This ranks in my top 10 skills to learn for any disaster--natural or otherwise.