I do much of my hunting with my 9.3 double rifle from deer in the east to bears in Alaska. Probably about 80-90% of my hunting is with my double rifle. I just picked up a Kodiak 58 muzzle loader so that percentage is about to increase! As long I know that I can limit my shots to under 175 yards or so I'll take the double rifle. If not, and thats not much of the time, I take my battered old 30-06 bolt action. To give you an example take last year:

Black bear in Alaska: 9.3 double
Whitetails in Virginia: 9.3 double
Mouflon where the adverage shot was 200 yards, I did take my 30-06. Some of the shots I could have pulled off with my 9.3 but it was a cull hunt with the understanding that we had to take as many animals as possible. So the bolt came along.

The real trick, as with any rifle hunting, is to know your rifle, and know the area and game to be hunted.