Without listing it all, I lean towards the more prepared end of the spectrum. I don't have a bus or train to catch. If I could lasso a moose, maybe I could hitch a ride back to wherever he is going. But that might not be in the direction I was headed. So in addition to just about all of the things you guys have posted, I also carry a spare brake cable and spare shifter cable, as well as a rag. I also keep a couple of short lengths of paracord (~18" each) that I'll use as third and fourth hands to hold a tire in place when mounting it.

For wrenches and such, I currently carry a Crank Brothers Multitool. In the past, I have just carried loose hex wrenches, and I sometimes wonder about going back to that. I like having the chain tool around. I've only had a chain break once, but it was an easy fix. I didn't worry about the broken link--I just removed it and put the chain back together minus that link. It rode and shifted fine for hundreds of miles before I was able to replace it.