The 30-06 and .308 are quite popular for Australian feral culling, for those using factory loads. When guys who buy and shoot ammo literally by the pallet swear that it works better than most its hard to argue. Its not entirely a price driven thing, I never thought I'd see blue box 30-06 sell for $42 a box. That was 2 bucks more than Norma in the same store, but that's the nature of import duties.
I'd be careful about short range with the faster magnums but standard calibers do well. It stands to reason that standard factory ammo is designed to make most of the people happy, most of the time if for no other reason than they want to sell lots of it. The farther you stray from "ordinary" the more you should question what you're doing that's is so special to warrant it.