safety/survival gear -- what do you carry?

I really need to get a small multitool and start carrying some spare parts -- one day I'll have an equipment failure and be sorry.

I read a survival book once that argued the best way to stay alive is to get rescued, and that having multiple means of signalling for help/your location was the most essential thing after maintaining body temp. I have a mirror and space blanket that is traffic cone orange on one side, but I need a whistle, and the flares seem like a good idea too.

Does anyone carry more medical first aid stuff than duct tape? Antibiotic cream, band aides and 2 inch gauze pads always seemed a little beside the point to me, but maybe I'm not enlightened.

Does anyone carry more medical first aid stuff than duct tape?  Antibiotic cream, band aides and 2 inch gauze pads always seemed a little beside the point to me, but maybe I'm not enlightened.

I think Duct tape and TP can simulate pretty much any bandage, and better. For instance you can make a pretty credible finger splint with enough duct tape. Duct tape can also be used to attach a larger splint (I have not had to do this).

It is possible that antibiotic cream is good but its presence or absence will manifest several days later - I don't think it affects your fortunes much same day.

Duct tape is seriously useful for temporary trail markers.

usually carry and have used at various times all of these in addition to your list:
barometric analog altimeter.
puffy jacket, liner gloves, light waterpoof overmitts, balaclava.
first aid supplies in ziploc bag incl a bunch of 4x4 gauze pads and adhesive tape and adhesive butterflies and latex gloves for wounds -- slices or gashes with lots of bleeding may need more than duct tape or a bandaid or 2x2 can do.
pencil and first aid incident report form and a few sheets of small paper -- it is really helpful to 2nd responders or go-for-help person to have written down name, time, location, condition info and amazing what I cannot remember a few minutes later including the full name and emergency contact phone no. of whoever I casually hooked up with for this trip.
Duct tape wrapped around a wood dowel or pencil and replaced 1x/yr. It dries out.
(used all my duct tape and adhesive tape last week to tape a companion's leather boot to her ski after the sole took off with the ski)
2 oz serrated knife
shovel usually.
light bivy sack if going somewhere remote or with route finding issues if stormy.
small partial roll of red surveyor tape for route marking, wrapped around extra lip balm tube.
extra bite peice for drink tube. 
extra batteries.
emergency calories -- fruit leather is about the lightest, thinnest, very durable, in the bottom of the pack.
4 feet of poly binders twine with overhand knots every couple inches, to use as a snow saw.
If in a stay-together group, not everybody needs to carry everything.

Does anyone carry more medical first aid stuff than duct tape? 

Something that I carry that I seldom hear mentioned are drugs.

In addition to a couple of naproxin and aspirin, I keep two Vicodin and two Adderall (amphetamines).
I don't remember where I got them of course but they are there if needed.

You mentioned a thermarest.  I carry a 2.5" inflateable pillow with primaloft (Big Agnes).  It rolls small and is convenient to sit on for extended breaks but would be a nice item during and unexpected overnight stay.

I keep two chemical hand warmers on hand usually.

Lots of duct tape.  A shovel handle is a good place for extra.

A cell phone can also be a good idea.

It is amazing how close to the road one can have an epic. I think the gear is important, but even more so are the skills and judgment you take as well. First aid gear without a first aid class will probably just stop bleeding. Traveling in the winter without an avalanche course will leave you in low angle trees with a high chance of trauma due to vegetation.

I adjust first aid/repair/clothes/food by the distance/difficulty and quality of my partners. The list in Martin's ski touring book is the most useful one I know of. At the very least I carry the holy trinity plus medical tape and gauze to be found, help with a rescue and make sure I can stop bleeding. Everything else depends on the route and conditions.