Tim,
My EDC might seem thin considering I have a bag hanging off the back of my chair (3"x14"x12") - -
Leatherman Charge
Whistle
Flashlights (4!) all mini size attached to various things
Cell phones (2) plus AA powered charger
SAK
Emergency contacts
Tums
Aspirin
Tylenol
Sig (ccw)
Water
Standard wallet stuff incl extra keys
Food (varies)
Lighter
Ipod
When I'm significantly away from home/office I carry a much more complete kit that includes FAK, water purificatin tabs, emergency "blanket," etc that's based on ETS suggestions (2"x4"x5") in a siliconized nylon kit bag with multiple pockets. I also would carry hot hands/toastie toes, hat, sunglasses, and so on depending on what I think I might need.
I try to keep the chair light and rely on being close to my van. A couple years ago we went out west (flew) for 10 days - that was different ... I carried all of the above plus maps, paracord, bandanas, and a couple of FRS radios for my wife and I to use. That all seemed good in hindsight.
From everyone's suggestions I'll add at least an armband light and nitrile gloves.
My FAKs are very complete but nothing special (I have a wonderful company FAK 40 ft from my office). Fortunately I don't have any real health issues (lookin' for some wood to knock on) beyond brittle bones, loose joints, and a fused back. I probably should carry some prescription pain meds but I get by on one aspirin a day a a couple Tylenol a few times a week. Mostly I wind up using my EDC and other stuff to help others
The people I know well ask me for a variety of things all the time. When my wife and I go out I carry her stuff too which sometimes includes her version of an EDC in addition to the usual (contact case/fluid, gum, brush, blah blah blah).