I know people will disagree:
The $1 knives at Walmart. They're actually decent. The design is pretty good, though it is made of crappy steel.
However, for $25 you can get 25 knives.
The one I bought for my g/f lasted a full summer of constant use (we worked at a boy scout camp) and then some. She still has that one and brings it camping.
I handed them out to the boys who completed their Toten Chit under my instruction. As far as I know, only 1 has broken.
EDIT: I personally carry a BenchMade with me everywhere I can.
this one:
http://www.rei.com/product/737698