The 9mm is the sidearm of NATO and the US Military. Choose a 124 gr. HP for carry and practice often with Win WB from Walmart. While there are larger calibers, the 9mm with proper shot placement will serve you well.
BTW, I have two 1911's and one Springfield XD .45 Service. What am I carrying this week on CHRISTMSAS (yes, I said it) holiday, my trusty Springfield XD 9 SC - you betcha!
Merry Christmas to you and yours!
