Commuting bike (In backpack/messenger bag/rear rack trunk): New tube, patch kit (only for emergencies - second flat), presta-to-schrader valve adapter, pump (Topeak Road Morph, baby!
), Specialized prybabies (The best!), park mini chain tool, folding set of allen wrenches, two small adjustable wrenches and a roll of electrical tape (Duct tape is too heavy/bulky). I too carry a headlight and clear UV lenses just in case it gets dark, and a cargo net to bungee down unexpected swag. I always keep a folded windbreaker back there and some painkillers....ya never know.
I used to also carry a set of folding screwdrivers and a small Swiss army knife, but someone gave me a knock-off leatherman (I call it the "Pleatherman") which does all that plus gives me pliers and a nail file.
After specific commutes, I've wanted to add a .357 magnum or a baseball bat at times (wait - are those 'tools'?)
Road bike (under saddle bag): two spare tubes, abbreviated patch kit, tiny bike multi-tool, mini swiss army knife. Same pump, strapped to frame or shoved in rear jersey pocket.