Most people do not live in areas where terrorism is, in my very humble opinion, a legitimate concern. You, however, do work in the District. I would have a bag with me at the times I'm in Washington that would have water, glowsticks, leather gloves, dust masks, a couple or three FRS radios, a few dollars in quarters for payphones, a bandana, and such other items as I could comfortably carry over my shoulder where ever I go.
Philip, thanks for the considered and thoughtful response. I'm working towards the goal being able to ride out some sort of interruption to "normal" life at home for a couple of weeks, I'm good now for at least a week. I do carry a substantial EDC in my work bag.
(see this post) My intent in writing the orginal post was to gain an appreciation of other's thought processes and considerations. For me it's been a very informative and useful discussion.
Long-term preparedness, however, is now simply a focus on providing those essentials for a reasonable period of time under the assumption that outside aid will be a day late and a dollar short.
And guess what - it's still kinda fun...
Well said, sir!