Welcome to the forum! Get them both! You're only lying to yourself if you think you'll only have one for the rest of your life!
If bears are included in the mix, I'd take the 10mm over the 357 if those are the only two options. Do you reload at all, or plan on reloading? If ya like revolvers, don't count out the 45 Colt if you reload. Very very versatile if you get a Ruger Blackhawk, Super Blackhawk, or Redhawk. It's one of my two favorites.
A lot of people are like a slinky: Not much fun till you push them down the stairs!