The effectiveness of a CCW firearm in real world situation is directly correlated to whether you have it with you. Therefore, the caliber selection should include finding a reasonably sized gun that you can holster, conceal, and have appropriate clothes for that does not become a heavy weight burden, to be left at home. Well prepared dressed, and equipped 1911 owners can carry day and night without being bothered by the size or weight. Smaller owners, who do not figure out a CCW wardrobe and holster set up may soon find a 1911 too much trouble, always pulling their pants down, printing, or other wise becoming semi-open carry. Smaller .380's, .38SP, 9mm, .40, etc, might be better in the long run for those folks. If you are considering a Judge, especially the new shortie CCW model, be sure to take all of this into consideration.
As has been pointed out earlier in the thread, caliber is only part of the story. Bullet and load are also part of the equation. Except for those poor folks living in New Jersey, I cannot imagine why anyone would carry ball ammo. Some form of hollow point is the way to go. Further, frangibles like Glaser bear a close look as maybe the best answer to overpenetration.
I am no expert on this topic, I just read a lot in the forum and elsewhere. For the size and weight aspect, I picked a .38+P snubbie (S&W 642), so that I have a decent pocket gun. And yes, I do practice at the range regularly (although not 300 rounds a month), generally at 7 to 30 feet.
Happy new year, all!
Craig