.380 or a .38 would be better than nothing but small cal. .357 is nice. 9mm is fast but relatively small with an advantage in cheap, available ammo. .40 cal's are excellent. .45's are my choice. .44mag is a beast. .50 cal - well you can figure that one out. Here is also a very nice option http://www.taurususa.com/video/taurus-theJudge-video.cfm

SA's will generally give you 10 - 15 shot mags while you'll get 5 or 6 will a revolver. I like having more rounds but for the most part if you have to use it for personal defense while in the woods you are most likely talking about relatively close encounter that if 5 or 6 shots isn't enough you probably wasn't going to do much better with more bullets.