.22 Magnum from a rifle is my favourite cartridge.
-Not loud (sure, there's a little pow, but it doesn't drown out the supersonic crack of the projectile; when you lose the supersonic crack to the propellant explosion, that's when you know what you're shooting is quite loud)
-flat shooting out to 120 meters (many loads are still supersonic at 200 meters)
-powerful enough for game smaller than deer out to 120 meters (it will work on deer ethically in many instances, but the shooter must be skilled)
-ammunition is cheap compared to .22 Hornet/.223 Remington, and it works on the same sized game just the same out to 120 meters as these two, which extend the range out to just over 200 meters for the most part
Whilst people are hoping for specific pistol loads, I'm hoping that companies put out more projectiles with higher BCs, rather than the common flat nosed stuff; stuff in the 35-37 grain range, which will offer less velocity loss downrange. No need for special brand named "wonder plastic tips" that kick the price up, just your basic pointed projectile (spitzer).