Pick what feels good in the hand and shoots naturally for you. The differences between calibers won't make any difference if you can't put the hole where it needs to go.
For myself, I'm partial to the 9mms. Springfield XD extended mag gives me 16 + 1 and I can rapid fire center of mass out to 30 feet. With spare mags, plenty of firepower, even if your target is high on drugs and feels no pain.