Semantics. . . What functions does an urban kit need to perform? Do you travel by car, subway, bus or bicycle? Are there elevators in your travels? Will the survival kit be EDC (implied) or will/can it be stored at work in a high rise office? If there is a car in your daily commute, a duffel can carry a huge kit for all sorts of urban/suburban/wilderness contingencies.

I'm not sure the question regarding natural disasters is relevant; an EDC kit might be a little different if you are in earthquake country (SOCAL) as opposed to tornado country (Mid-West) during the season -- but I suspect a lot of similarities.

Big knives are out, but are multi-tools in? Personally I like a locking folder in addition to a multi-tool. I use the folder more, but a good multi-tool has so much potential I carry one in my EDC back-pack even though I rarely need it.

What is your every day carry? --part four has some great ideas for urban carry. Your post in that thread is a very good urban kit IMO.

Most important items to me are:
1. Water
2. FAK
3. Flashlight
4. Knife/Multi-tool
5. Whistle