5 rules of a gun fight:
1) gun beats no gun.
2) fast beats slow
3) a hit beats a miss
4) bigger bullets beat smaller bullets
5) two holes beat one hole
To your specific question, I would agree with either 9 mm or .357 mag. Both are widely available, both work well in pistol and/or carbine. Both are often reloaded.
I am of the opinion that there is a slight advantage to the .357 because when shooting / practicing gets expensive, you can also use .38 special.
Good point, and I already have a .357 revolver for home defense (but not a closet of ammo for it.)
How has 9mm ammo been running cost-wise vs. 357 and 38 special, over the last year? (I'm not sure how valid a spot check right now is, what the trends are...)