I carry a fair number of tools. I carry a wrench for bolts, leatherman juice 2 multi-tool/knife, hex wrench multi-tool, S&S coupler wrench.
I carry extra tubes, patch kit, tire levers, frame pump, tire boots.
I carry extra spokes for both rims, hypercracker tool.
I also carry an replacement for every bolt on my bike (see this thread for why:
http://www.bikeforums.net/showthread...-a-replacement).
Ray