I have an antique .36 I just love, and if I had one gun to survive with, that would be it.
Of course, it's NOT legal for deer, but a close shot (and it's accurate as all heck) would take one down, I'm sure. In a situation where one gun had to do it all, I would pick that .36 over any other for general game.
Since I live in the real world, I use a .50 for deer, and have a new .58 I haven't taken out yet. Of course, I have the luxury of owning several rifles and, in the old days, that wasn't always the case. You made do with what you had.
David L