If you want a light multi-tasker rifle, .243 is a nice option. You can shoot 55 grain bullets for small game and varmints, and shoot up to 115 grain bullets for medium to large game. .243 is flat shooting, long range, low recoil. It also has a larger variety of ammo available than the others you mentioned. I shot a whitetail yesterday with 95gr Hornaday Light Magnum SST and it performed flawlessly (MV 3100 fps, ME 2027 ft. lbs).
Whatever caliber you go with, I would definately get a short-action rifle so you aren't lugging around extra weight. My Kimber Montana is only 5.5lbs and is a pleasure to hike/hunt with in the field.