Yeah, it's been way too long since I've posted about anything that goes bang.
Via The Survivalist Blog, PappaDeltaBravo has a good picture of the permanent wound channels from various handgun calibers. Note that every caliber and loading has a minimum penetration of 12", enough to reach the vital organs in the human body not matter what the angle of entry. Also note that the permanent wound channels are all, relatively speaking, the same size.
What I'd like to see is some high-speed video of the temporary wound channels. My suspicion is that those, along with absolute shot placement, are the prime factors in whether you get a quick stop with a handgun round or not.