One of the problems I see with the question is the reference to an "all-purpose" rifle. It reminds me of the discussion (for lack of a better word in the thread on Col Cooper and his Scout Rifle idea).
There is no such thing as an "all-purpose" tool which performs all tasks as well as the specialized tool. Anything which is all-purpose will not be optimized in any one area, but will be able to perform to some extent in all areas. To get something, you will have to give something.
My answer would be that the best rifle would be the one which you have and are proficient with and can carry. If you don't have it, or cannot shoot it well, then it will most likely not do you much good.
My personal preference would be for a Colt AR-15 or clone. I can shoot it okay (look, I'm not a rifleman, YET), and i can grab it and a good supply of ammo and go.
An M1A or similar class rifle would be a good choice with more punch and range, but also more weight to carry.
But in the end, it's what you have and can carry and shoot. Look at the options, make a careful choice, then go with it.
There is no such thing as an "all-purpose" tool which performs all tasks as well as the specialized tool. Anything which is all-purpose will not be optimized in any one area, but will be able to perform to some extent in all areas. To get something, you will have to give something.
My answer would be that the best rifle would be the one which you have and are proficient with and can carry. If you don't have it, or cannot shoot it well, then it will most likely not do you much good.
My personal preference would be for a Colt AR-15 or clone. I can shoot it okay (look, I'm not a rifleman, YET), and i can grab it and a good supply of ammo and go.
An M1A or similar class rifle would be a good choice with more punch and range, but also more weight to carry.
But in the end, it's what you have and can carry and shoot. Look at the options, make a careful choice, then go with it.