best defensive caliber and why?

[Rocky_Raccoon]

I'm primarily looking at pistol caliber but I know ill get the occasional 12gauge reply but for good reason... anyhow looking at standard home defense/ carry caliber I want what you use and why, I.e. statistics, trade offs, ammo selection, all you have to bring to the table. Personally I carry a hk p2000sk in .40 most of the time because I'm 160lbs soaked and wet and I can only get away with a full sized 1911 in fall/winter. I perfer .45acp 1911 which is what is on my night stand and belt when its sweatshirt weather. 45 is my choice on the grounds that worst case senerio my bullet doesn't perform as its supposed to (fail to expand, or just so happen to just have ball ammo in the gun) . I still have a half inch bullet ripping through your torso... any other opinions?