As someone raised in Alaska, I'll second the 30-06 as good general rifle. You can hunt with it, practice with it, and find ammo anywhere. Good 180 or 200 gr bullets would suit you fine, leave the 150 and 165s for the lower 48 (though 165 do good for long distance on smaller game). Other pretty common calibers that Alaskans use: 7mmRM, 300 WM, some of the Weatherby's and 338WM. You generally don't see that many Alaskans running arround with the guns that visiting hunters from the lower 48 tote arround (I've seen very few 375s really being used by Alaskans)

It does depend on what you really want the rifle for. A general hunting rifle for moose, black bear and maybe caribou and target practice is different than a rifle only to be used for bear safety: ie. shooting at close distances, and stopping charges. 30-06 is flexible, low recoil and cheap ammo. Most of the big boys for stopping bears are not as cheap, have a heavier recoil and are not rifles most people use as general purpose rifles.

I might draw some flak here, but generally speaking you just don't need to constantly carry a bear gun with you at all times in Alaska. I grew up both near Anchorage and in the interior arround Fairbanks, have spent time in the Southeast coast too, and spent a lot of time fishing and birdhunting without a big rifle. Just practice good bear habits and use common sense you shouldn't have problems with bears. Of course there are exceptions: salmon rivers, areas with lots of bears (Kodiak etc), and arround dumps/parks that might have problem bears.

Just my thoughts.