I guess my answer to the original post would be to say that the 30-30 has probably killed more deer than any other, but it has been around longer than most others,too. The 30-06 is PROBABLY the most used round for all - around big game hunting in North America, mainly due to the wide variety of factory ammo available for it, along with it's excellent reputation. With that said, I would personally perfer something a little larger for the BIG bears, but the '06 certainly has accounted for it's share also
I also have to agree with the fact that the .270 Win. has a huge following also, and feel the others fall in line somewhere. Just my opinion ..