If you don't reload the best option is the .44Mag. Simple as that. There are a many more factory options available to you than .41 or .45 Colt.
If you reload, then the .45 Colt is the way to go IMO. Been going strong since 1873 and has gotten better with age. Load up or down depending on your needs from powder puff to Cape Buffalo loads in the right revolvers.... You just can't go wrong with a Ruger Blackhawk or Bisley.
A clinger. When guns are outlawed, only outlaws will have guns. Single Action .45 Colt (Sometimes improperly referred to by its alias as the .45 'Long' Colt or .45LC). Don't leave home without it. Ok.... the .44Spec is growing on me ... but the .45 Colt is still king.