I have a Swiss Army knife type device but it's a flat card with a small pair of scissors, small knife, screwdriver, pin etc in it. Someone bought me it as a simple gift years ago I take it just about everywhere I go, sometimes I'd be lost without it.
A couple of toothpics, incredibly fustrating not having them when you need one.
Camera, batteries, chargers, glasses, torch, mp3 player...? It very quickly all starts to add up. I was always amazed and how much crap I'd take on a weekend trip (non-flying) must of which I never used but knew rightly the time I didn't take it would be the time I need it.