Keeping in mind one's intended purpose, and mine being hunting, it would be what I have now - a Taurus Raging Bull in .454 Casull. Granted I own several other handguns, but the .454 would be it. Why? Winchester offers, or at least they used to offer, ammo with reduced loads that kick like a .44 mag. And when you want full power loads, you can use 'em and feel confident.
Zachary