.40 .45 or 9mm

[severous01]

question as stated, 40 45 or 9mm. i'm lookin at a springfield XDm and i like the 9 because of price of rounds and i'm not looking to spend a ton in bullets. i like the .45 because of stopping power. most rounds fired will be down range. it's for personal protection only, nothing more than staying in the house or goin to range.

any assistance would be appreciated. thanks in advance.