With bullet technology where it is today there are a few manufacturers you can always count on. Caliber aside: Federal Hydra-Shock, Winchester Ranger, Golden Sabre, Corbon DPX, and Speer Gold-Dot are good solid rounds to use for personal defense ammo.
These all expand well (or well enough) to kill. More important than anything is shot placement. No matter what round you use, if you do not put it in a vital area, well, I'll leave it at that.
Myself, personally: I use a mix of Winchester Ranger (Black Talon) and the Corbon DPX. in a 13 round mag, I will use the first 6 rounds of Winchester Ranger and the last 7 rounds of Corbon DPX. Why? Because if I have to go beyound 6 shots at a bad guy, it is only because he is hiding behind cover and the excellent barrier penetration and wieght retention of the DPX means that I can shoot through most common barriers and hit the bad guy with as much wieght as possible.
What about velocity you ask? Well being that I use the .357 sig round that is traveling at a screaming 1,450 fps (custome load) going through barriers witht he DPX round, although the round does slow down, it still has enough velocity and energy to destroy the intended target without over penetration.
The Virginia State Police have had several documented officer-related shootings involving the .357 Sig, and in every case, not only were the felons stopped instantly with one shot (except one who was shot several times while attempting to murder an officer), the bullet either didn't exit the felon, or was stopped in the clothing upon exiting, proving that even at such high velocities, the round when used with adequate expanding hollowpoints will not over penetrate soft tissue.
There has been a documented case in Texas where a police officer's .45 round did not penetrate a tractor-trailer's shell, but a .357 SIG round from a backup officer's gun did, killing the suspect inside.
Sorry to get on a rant, but I love this round and as more and more LE orgs are using this round, the more we will see the real benefits.
125gr .357 sig - 1450 ft/s. 580 ft/lbs
I just wish they would make a revolver with this round. Although, I am looking at the Federal .327 for the wife.