I prefer not to think of an urban survival kit as a single "kit," but rather as a continuum of choices. I carry phone, SAK, photon flashlight (actually, a fauxton), whistle, and money on my person pretty much at all times.

I think it would be a poor choice to have these items tucked away in a self-contained kit because these items are daily use and/or need to be immediately accessibe.

I keep additional resources in vehicles and in the house.

At work, I keep a waist pack in my office in the event of an emergency evacuation. It inclues dust masks, water, knife, OTC pain medication, benadryl, adhesive bandages, sun block, flashlight, energy bars, whistle, paper, pencil, duct tape, super glue (liquid wound closure), moleskin, compass. Based on comments in this topic, I intend to add a map, immodium and a pocket radio to the waist pack.