The most desirable knife steel I've seen is the MeierClad san mai damascus with a 52100 cutting edge core and damascus outerlayers. It is pretty, tough, and holds an edge quite well, I imagine. I have to imagine 'cuz the only knives I've had the opportunity to buy made of it were Bud Nealy knives and I didn't care for the design.
Second place goes to any low alloy tool steel that can be differentially heat treated for a hard everlasting edge and a tough spine: 52100, 1084, and O-1 in particular.
But I guess my real second choice for a working knife would be CPM420V (S90V now?). It is pretty tough, pretty corrosion resistant, and holds an edge like crazy.