I haven't found "the one" knife, because there's no reason to limit myself to just one knife. But I have found a few that are just about perfect.
Case 6332 stockman - perfect blade assortment, and halfstops.
Case 6318HE - perfect blade assortment, and nice curves
GEC #47 sheepsfoot Hayn' Helper - I wanted a sodbuster like knife and I always admired those big wooden handled Ottermessers from Germany and sheepsfoot jacks from Sheffield, and GEC answered my prayers for a cross between the two.
2004 Case/Bose muskrat - the Hawbaker muskrat is probably my favorite pattern, and with great F&F, all steel hardware, half-stops, and ATS-34 steel, this knife is perfect.
I'm sure the GEC 92 Eureka jack will be perfect whenever I can afford to get one. Or three.
And then of course there's the upcoming 2013 Case/Bose 3.5" wharncliffe trapper. That'll be perfect too.