I've never patched a flat. I carry a spare tube (or two, if its a longer ride), 3 tire levers, a multi-tool that has most of the common stuff, and a spoke wrench. I sometimes throw in a couple of allen wrenches in the most common sizes, just because they're easier to use than the multi-tool. Oh - and a pump, water and cell phone, of course. A lock, if I'm going to be leaving the bike.
Not forgetting your keys is also a good idea. DAMHIKT.