My daily bike wears a Carradice bag which I kept stocked with tools. I carried light, small versions of chain tool, metric box wrenches, allen keys, screwdriver, spoke wrench, all fitting the fasteners on the bike. I also carried extra shifter and brake cables, a few extra bolts and nuts, patch kit, tire boot, tire levers, two tubes, pocketknife, and energy gels. One day some lowlife stole it all from the bag. I've since rebuilt the set but not as nice as it was.

On other bikes, I've carried the little plastic Mafac pouches with the stamped Mafac tools. Those really are perfect for bikes of a certain vintage, that use hex bolts instead of Allen fasteners.

On my roadie rides, I carry a Park MT-1 tool, tube, CO2 cartridge and inflator, and minipump, which all fits in a jersey pocket.

Lately I have taken to packing bike tool stuff into my messenger backpack which I use in place of a work briefcase. I have a multitool, tubes, CO2, mini pump, levers, patch kit, energy bars, and latex gloves in addition to pens, notebook, business cards, computer, files, papers, calculator, mini umbrella, and all the electronic/computer accessory stuff that follows us around (chargers, cables, mouse, etc). I also carry some rain pants, gloves and a rain shell, rolled up to be padding for the computer, and clip a blinky to the bag flap. Sometimes other stuff gets in there and I don't notice for weeks - the other day I was cleaning the bag out and realized I've been carrying a full water bottle and two pairs of dirty socks...

This is one of the large Chrome messenger backpacks, I've actually traveled for four days with only this bag, mountain of stuff can disappear into it, worse than the average lady's purse. It's not terribly business-like to bring into meetings, but in Portland no-one looks twice. The loaded bag weighs a ton (some days over 25 lb) and my commute bike is heavy too (about 35 lb, with the usual gear and U-lock) so I do appreciate the days when I'm on the roadie bike.