If you want just one rifle for all three I would suggest one of the various .338's. If the Brown bear hunting is still far into the future, I would go with a deer rifle that can double as an elk rig e.g. 30-06 or one of the .300 Mags. IMHO it's about personal preference, how you handle recoil, and budget. Most of all have fun with the process and let us know what ya end up with.