Wow what a interesting triad from which to choose
The .45+p is a legendary manstopper. The 10mm can do what the .45 can do, and gives you enough extra power to hunt, though in the right gun the .45 can match the 10mm. The 20 makes sense for a camp gun in black bear country as well as the urban jungle. Ammunition is harder to come by and is more expensive than the .45 or .44 (for me, anyway). But if you don't need bear protection, it is a nice round. Now if you want something that can truly do it all, from stopping bad people to hunting and grizzly bear defense, the Ruger .44 Magnum (+p+) is the most prudent choice of the 3.
I wound up with two guns- a .45 as a BUG to the .44 I think I am well covered on the streets or in the woods. I chose the .44 and .45 over the 10 simply because of ammo cost and the fact that I can make my .45 almost equal the 10mm, and the .44 trounces it in power and versatility.
Shooter429