IMHO the .338WM is the best N.A. cartridge for moose/bear*. It's got plenty of power, flat shooting, mild recoil, is readily available from every major firearms manufacturer, ammo is available etc...
Handload 225 or 250gr bullets; Hornady IL, Nosler Partition, Speer GS, etc...
If you don't handload, no sweat; just head to Canadian Tire, Wal-Mart, P&D Enterprises etc... and buy some factory ammo. It almost doesn't matter which brand.
* The .375H&H, 9.3x62 or 9.3x64 are also awesome moose/bear choices.