At the very least you also need CO2 or a frame pump. (What good is a spare tube if you have no way to inflate it?) I go with CO2 because I don't have any place to hang the pump, I have bottle holders everywhere. My multitool includes tire irons and spoke wrenches. The first-aid kit comes useful sometimes, as does duct tape.

The only things left are the presta adapter (tiny and light), the patch kit (light), and the $20 bill.