Like you'll hear frequently here, shot placement is infinitely more important than the individual round you choose. But that said, I find myself rotating between the Remington 165 grain Golden Saber, and the Corbon 135 grain Powrball. Those are just two of the more consistant rounds I've tried and I'm comfortable with the performance I've seen from them. If I can get my hands on some of the .40 DPX I'd love to try them out, but I have trouble finding them..........and just about everything else from Corbon.
Bottom line: Experiment and find out which rounds your particular gun likes, and which ones you shoot the best with. That'll be the round to use.
---Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.---
---Enlightenment is the ability to take infinite pains---