My on-the-bike toolkit:
* 6" adjustable wrench
* 10mm combo wrench (my brakes need two wrenches to adjust them)
* 3mm, 4mm, 5mm, & 6mm hex keys (these are the sizes I need for my bike)
* dual-head L-shaped screwdriver
* tire irons
* chain tool
* extra links
* fiber-fix spoke
* double-sided velcro (this stuff is awesome, it's like reusable duct-tape)
* zip-ties
* rag
The whole thing rolls up into the rag and is secured with the velcro.
It's a little on the heavy side (17 ounces), but there's not much you can't fix with it. Brakes, fasteners, shifting, broken spokes, etc. Pretty much any basic maintenance.
The whole thing only ran me about $25 or so, and the fiber-fix spoke counts for a lot of that.
I also carry a pump on the frame, and a tire patch kit with alcohol swabs, sandpaper, patches, and glue.
At home, I have a cassette tool, a chain whip, a bottom-bracket tool, spoke wrenches, a pin spanner, cleaning brushes, solvents, and grease. A few extra hex keys, cable cutters, a 14mm socket, a 15mm open wrench.
I may have missed something, but I think that's mostly it.
I built my tool-kit from the
advice given in this post.
It's amazing how much I can do with my tool-kit. I have been seriously considering building a second kit to keep in the car, for when I help other people with their bikes.
One thing I haven't figured out how to carry, but which I'd like, is grease. How do you carry your grease? I'm worried about the grease melting, or the container coming open, or somehow or other making a mess. I don't really want all my tools and my patch kit and my bag getting covered with grease. You say you're carrying it -- care to share how?