If you mean for self defense the short quick answer would be a 30-06 or larger rifle, or 12 ga pump with premium slugs. For casual wandering I wouldn't exclude a 270, 308 or similar, if that's what you happen to have. Remember weight and bulk become a real factor if you are bucking much brush or climbing.
For most convenience a 44 mag or larger hand gun.
Most important would be your ability to shoot well what ever you carry.
Second, while it can be a good idea to carry a self defence gun it is not always necessary - this "need" gets way overblown in AK. As a kid we snicker spotting the Cheechakos with their 12 inch bowie knife and 44 mag on the hip with a full cartridge belt and shouldering a monster mag rifle just togo to the camp ground outhouse. A litte discretion in use and carry is encouraged - especially in higher use public areas.
Probably the single most versitile weapon is a 12 ga. Can be used for small game and waterfowl, self defense, and properly rigged even for some big game hunting. Pump would probably be first choice for me.
Now if you expect to intentionally go into hazardous country, remote salmon streams at spawning time or hunt bear you can explore this forum for the endless discussions on the topic.