This is a hypothetical question and if I read into it correctly, I think what is presented is a survival situation where you need to survive in the wilderness with just a single field pistol so with that I mind, I stick with my original choice the Ruger 22/45. Sure, there are other weapons that would serve better like a shotgun, but for a "field pistol" I would take my little .22.
100 round of .22 would be enough to put some small game in the pot and it isn't the best for defense, but it is better than a pointed stick :shock:
Also I won't be spending the day shooting at tin cans to pass the time since your survival is on the line, so I would pass on having gun oil, patches, cleaning rod, borelight... A good flap over holster would suffice and I can clean my pistol when I get resuced.
If there were no rules and I could bring what ever I wanted, I would have one of these <img src=http://img150.exs.cx/img150/1908/jeeprescue5fc.jpg> fully stocked with food, water, sleeping bag, tent, dvd player, folding chairs, air matress, kite, and......... :mrgreen: