Ah, but for me it depends on so much..
Are we talking about simply being allowed to only own one LM?
Or are we talking about the old "on a desert island" scenario?
And can I have additional tools with it?
I suppose I'd go with the Surge for most of those situations, but I am leaning toward the desert island concept. Big blade, scissors, OHO, awl, large pliers head, etc. (..and the file doesn't rub

)
But if it is merely that you can only own one LM... I might go for the Charge TTi, or the ST300 due to these being the pinnacle of LM design right now.. or maybe my old ST200 for sentimental reasons.. or one of those fancy expensive Argentum Charges just 'cause you said I could only have one.
But if it is for splitting open coconuts, gutting fish, and making a shelter, I'm going with the Surge. I can always use it to anchor the raft I build with it to escape the island. Or I can heave it at monkeys in the trees for meat.