Brookielover,
You have gotten a lot of fine advice from some very knowledgable people, but I would differ on a couple of minor points. I would not use a 357 on whitetail size game with anything less than an 8" barrel. I know people who have killed deer with a 22 pistol, but that does not make it an humane hunting caliber. The 4" 357 is my goto gun when hiking, but I do not have black bears to contend with around here. I have a Dan Wesson 357 (a couple actually) and that is what I carry, although it is a little bigger than most of the fine guns recommended above. I am a big guy, so I never notice it while hiking.
If bear defense is in the picture at all (and possible deer hunting), you better go with the 44(or if you handload, a 45LC with hot loads.) The S&W is great in that it is a very light gun for a 44 mag. The only problem is that they tend to shake loose with a steady diet of HEAVY 44 shooting, but for a gun carried a lot and shot very little, they could be just the ticket. Also remember that the lighter a Magnum gun is, the more brutal the recoil is going to be and the slower the followup shots are going to be (if needed). Another option is a single action Ruger with a 5.5" barrel. It will be about the same weight as the S&W 29 or 629, but it will be a lot stronger. I just don't like to carry a single action for dangerous game defense where the shooting may be close, fast, and instinctive.
I personally carry a Dan Wesson 44 mag with a 4" or 4" compensated barrel for dangerous game protection when I travel and hunt out west. It is much heavier than the S&W, but it is much more accurate, controlable, and faster to shoot than whatever is in second place. In 5 minutes I can change to a 6", 8" or even 10" barrel for hunitng if need be. I really like that. I have head shot rabbits for the camp pot, offhand at 30 to 40 yards, with the Dan Wesson 44. It is a goody, not to belittle the other fine choices above.
Roll Tide