You are guaranteed to get some responses on this topic; there are quite a few threads that discuss knives and there are some pretty good ones offered for sale on the ETS home page. The Kabar is certainly a classic.

I think the best knife is one you feel comfortable with, and the one with which you are familiar. The need for a knife depends greatly upon the circumstances and the situation and its duration. Very often the means for lighting a fire and/or the means for signalling (signal mirror) will be more important than a cutting instrument. Sometimes a knife will be all important - I don't know if this is true or not, but I have hear the Ka-Bar was developed so that a downed pilot would have the ability to cut himself out of the fuselage of a crashed aircraft.

I am quite happy with my Wave multitool; I would be almost as well off with a good SAK.