If I had to pick one to be my only pistol it would have to be a Glock 19. It is a great weapon, reliable, light, compact and goes bang every time you pull the trigger. Load it up with Winchester Ranger 127g +P+ ammo and you are ready for a decently large set of zombies. I generally carry its little brother Glock 26 with same Winchesters and a set of CT grips in a VM2 holster with a G19 spare mag and spacer. That gives me 26 rounds of really decent stopping capability.