There's no one definative best ammo for self defense. Some people like Double Tap, Speer Gold Dot, and so on. From my limited knowledge about Double Tap they seem to like to load their ammunition near the top of the power scale.
"It's a gun you loaded on Sunday, and shot all week."
"If God didn't create man equal then Sam Colt had made them equal."
"Fast is fine, but accuracy is everything."