The one caliber I would immediately rule out is .40. I have heard or read of more gun explosions in .40 than all other calibers combined, and the one time I personally saw a gun blow up, it was a .40. The .40 will penetrate to about the same depth as 9mm, and the wound channel will not be significantly wider. The .40 might hit harder and make a slightly bigger hole, but I am unconvinced that a bad guy will notice the difference.
The previous federal 10 round limit was one factor that caused me to get a .45 1911. For concealed carry, I am quite happy with a Glock 26, regardless of whether capacity is limited to 10 rounds. I can shoot my 26 very close to as well as I can shoot my 19. The .45 Glocks are a bit thick for my hands, but remain shootable for me.