When I actually get to use a rifle and not a muzzleloader or shotgun, I use a .30-30. I also have a .280 and if limited to one rifle, I'd opt for that one. Most shots around here are within 100 yds, but it would be nice to have more range. If I had to buy one new gun though, it would most likely be a .270, .308 or .30-06. Should be plenty for deer, black bear, and hogs.
-Kevin