G20...it's the only one I have, and obviously most of the time you don't shoot it, you just point out where it says "10mm Auto" and at least half the combatants just give up on living right then and there.
If it was for self-defense, I carry a G23.
If it was for battle, then it would be a G23 with a 9mm and a .357 sig conversion barrels with a couple G19 mags. You never know, what kind of ammo you may come across. Best to plan ahead!