Depending on your finances, either Leatherman Wave or Victorinox Multitool. The Wave is lighter with one handed opening but the V.M is better made. I have both, and it's a toss up as to which I would reach for first.

Farther down the market, the Gerber's and S.O.G'S are probably the next choice. Everything else comes under also ran's.

Don't bother with the far east knock off's - unless you know that your likely to break it. Doug does a very interesting set of reviews on the main site. It's a bit dated but worth a read.