One reason to NOT carry with an empty chamber that I have not seen mentioned is the possibility of mechanical failure. When I load my gun in the relative safety of my house I have the ability to chamber the round, open the slide slightly to verify there is a round present in the chamber and the extractor is pulling the round like it should, close the slide again and verify the gun is in full battery by checking that the rear of the slide is flush against the top of the gun's frame. This eliminates all possibilities of a failure to feed. The only mechanical failure left on that all important first round is now a failure to fire.
I would rather deal with a failure to feed in my own home than on the street with a bad guy breathing down my neck.
To me, every excuse for not carrying with a chambered round is solved by a good holster and a good gun and minimal training and attentiveness. A good holster will cover the trigger sufficiently to avoid a negligent discharge in the holster. A good holster will retain the gun sufficiently to prevent a gun grab. A good gun will not discharge when dropped. Minimal training and attentiveness will minimize the chance of a negligent discharge while unloading/loading the gun if I have kids at home and will ensure that if I have a negligent discharge that the round will go in a safe direction.
We cannot predict when we will need our gun or under what circumstance. You say you can rack the slide in enough time. You say you are in a safe enough environment. But how do you know? How do you know you won't need your weak hand to push your wife behind you during an attack, or to push against the attacker who got the drop on you? Do you know that some nut job who just got fired isn't going to come back to your local Wal Mart or grocery store with a gun?
To me, carrying with an empty chamber is only intentionally introducing an unneccesary handicap which limits my possible self defense action. Why would I want to introduce that handicap?
That being said, I have absolutely no concern at all if someone else decides to carry an empty gun or if someone else decides to not carry a gun at all. It's their life, it has no affect on my ability to defend myself. But keep in mind that there is a universal rule that applies to skydiving and self defense:
When you are skydiving, once you exit the airplane you have the rest of your life to effectively deploy your parachute. Once I exit the airplane is NOT the time to decide to pack my chute into the carrier, regardless of how proficient at packing a chute I am.
When you NEED to use your gun, you have the rest of your life to effectively deploy your gun. Once I have determined that I am going to need my gun to defend my life is NOT the time that I am going to make the gun ready to fire.
I wouldn't pack my parachute in the airplane before jumpig or after I have jumped. I won't make my gun ready to fire on the street or after the bad guy has already attacked me.
Really?......I guess you could be right though. 
