The 45-70 is one of the finest big game hunting calibers on the planet. I would get the Marlin 1895 Guide gun in 45-70 and put a nice 2-7x scope on it. After you do that I would go to Garrett Cartridges' website and order some ammunition! If this doesn't convince you to get a 45-70 I don't know what will!

www.GarrettCartridges.com