For a hunting rifle, first check with your local fish and game regs. That's the bottom line. No use getting all worked up over a nice .45, only to find it is not legal for what you want to do.
As far as paper punching goes, it don't take much to poke a hole through a sheet of paper, but it does take some oomph to knock over a bear at 200 yards when you are shooting silhouettes. Personally, I prefer a .54 for all of my shooting. Well I lied there, I do like a .62 for deer size game and a .72 for elk and larger, but you did ask about a .45 vs a .50. That's just me.
If I had to make a choice between the .45 and the .50, I would probably choose the .50.