You can't go wrong with a Leatherman Wave or Victorinox Spirit, but if you want something smaller you might want to consider a Swiss Army Knife and a Smaller tool like a Skeletool or Gerber Octane.NOTE: I tried a Skeletool and didn't like the ergonomics one bit, and I'm not alone - but others love it. If you are tempted to get the Skele, try to play with one in person first to see how it feels for you in hand. It'll either feel really good or really awkward
Seems solid enough for light duty when my toolbox isnt at hand.