Depending on the length of the ride and the crappiness of the roads I carry one or two tubes and CO2 cartridges, no pump. I switch tubes and patch at home. If I "expected" to need 3 tubes I'd carry a pump instead.

But I always carry a cell phone, and in my neck of the woods I can either catch a bus, call home or call a taxi if necessary.

But this is also because I rarely flat (pretty good roads and Conti GP 4000 tires which have a good rep for flat resistance) and don't have a good frame pump. I've helped others with an CO2 cartridge or tube more often than I've used it myself.