.454 been around since the 1959. I don't think it's going anywhere, they're all the rage up here, that and the .500 S&W.
Seems like before the .500 became popular everyone had a .44 Magnum for bear. Now that these high energy exotics are in vogue the Alaskan market alone will keep the round alive for at least another fifty years, maybe indefinitely.
With that said, .44 magnum would be my choice.