I'm fairly new to the site and am just now feeling my way around the forums (fora?). Bear with me here... =-)
I vote for the .22 as the EOTWAWKI gun of choice. I have several in the safe, plus three older ones in underground storage, each with a brick of ammo, and a 12 gauge single with 50 mixed rounds in underground storage.
If I had to bug out with only one gun, it would be my carry piece, a Commander .45. In the go-bag under it on the shelf are 5 loaded mags plus 100 mixed rounds in a plastic box, a Ciener .22 conversion with a brick of hi-velocity HP, plus some emergency food bars and water. Since I'm 68 with a semi-invalid wife, bugging out is unlikely, but I believe in preparedness.
I was stationed in Alaska '75-'78, did lots of backpacking and recreational prospecting. Carried a BH .45 LC, 250 gr Keith-style hardcast over 9.5 grains of Unique. Still have the BH, still like the load, also use it in a Puma lever. Either piece will take out feral hogs. Had three encounters with bears up north, never had to shoot one, none around where I live now.
If I was just out looking for bears, I'd take a long gun with large bore and heavy slug. Otherwise, a pistol is handier if you're just out in the woods and don't like to be unarmed. Won't argue about which calibers are better. Use whatever you're comfortable with. I simplified my battery to mostly things that shoot the .45 ACP or the .45 LC, have several of each.
For mutant zombie UN troops offloaded by black helicopters, with Hell's Angels doing recon, I have some hi-cap rifles that I buy bulk ammo for and a couple of 12-gauge pumps. For most reasonable scenarios, I vote for the .22 LR.