Shoes are an issue. I choose shoes I can wear all day, but walking home after the Big One would be daunting. I should carry blister pads anyway as I do sometimes need them in non-emergency situations.
TheSock mentioned maps. That's something I haven't considered. I have maps in the EK, but not in my pocket. I do tend to explore rather than always driving the same route from A to B, so I know my way around pretty well. Still, a map would be nice. Trouble is a map with any detail would be too big to EDC. That might be one of the things I buy when needed.
A second pair of shoes and/or clothes in a gym bag won't be out of place as many people change and go to the gym before or after work.
Have a PDA/Phone/PDAhone? I store electronic maps on mine as well as my handheld gps fits in my laptop bag during the week, it runs on a set of eneloop AA's so its always ready and I've ran over 16 hours on one set so far.