Dropping off the first page... time for a bump...
My personal favorite handgun cartridge remains the venerable old .45 Colt. I "use" it for just about every chore suited to a handgun.
Low velocity, low pressure plinking loads comprised of a 250 grain cast bullet over light charges of W-W 231 or Unique go about 800 fps with minimal recoil. The same bullet over a full 40 grain charge of FFFg black powder will sneak up on 1,000 fps from a 7 1/2" barrel, and give us the full experience of the original loads. These are shown on the left.
Next up is my "+P" load, a 270 grain cast bullet loaded over a stout charge of 2400. This load is suitable for both sizes of Ruger single actions, as well as limited use in modern made Colts. It will touch 1,000 fps from a 4 1/2" barrel, 1,100 from a 7 1/2". It's the one in the center.
Finally, on the right, is my "bear load". It's a 300 grain cast bullet, which I load over a pretty stiff charge of W-W 296 or H110 (they are the same powder) for over 1,200 fps. This is decidedly a large fram Ruger only load. It would completely disassemble a Colt. Notice, too, its overall length is longer than the other two. It's too long to fit a Colt or small frame Ruger cylinder, providing a definitive safety feature to prevent any accidents.
Here is a pretty good representation of why we don't want to mix these up. On the left is a cylinder from an Interarms Virginian Dragoon, which is another single action of the size and strength of the large frame Ruger. On the right is a Colt cylinder. The difference in cylinder wall thickness is quite apparent.
So, granted, hand loading will provide similar versatility to many other revolver rounds. The .44 mag has a similarly broad range, for instance. What I like about the .45 Colt, though, is it will meet or beat .44 mag ballistics at far lower pressures. These lower pressures translate to less "bark", less noise, which I find quite noticeable when hunting. It just doesn't sting the ears as much and, since I really don't like hunting with ear plugs in, that's important to me.