I've always felt that the best "one knife", whatever the thecontrived circumstances behind the question, is going to be my Vic Mauser. It has 2 large (though non-locking) blades that handle different chores; plus it has the combo blade: saw, can and bottle opener, and straightslot screwdriver. On the back of the knife is a really well designed awl, long enough to be truly useful, as well as the corkscrew who's main function is to hold the tiny eyeglasses screwdriver. If you have only a single knife I think you'd be best served by a knife that can be used to make other implements while in the bush. While a large, locking blade is "sexier" and certainly stouter, it's also a lot less versatile.
The best option would be if somebody made a survival folder with the large, sturdy, locking blade AND the basic tools from an SAK.
In the spirit of the question, however, I'd go with my BM 9050 Auto. Not for the auto-opening fature; I'm actually faster with my BM 720. The 9050 has a larger blade that's better suited to use as a survival knife, and a better handle than the 720. Another excellent choice woujld be the SERE 2000, but I prefer the lock on the 9050, being left handed.