I started with 9mm and .40 S&W for pistols. Although I still enjoy them... I find that I'm really liking .45 ACP lately. I've been shooting my S&W 1911 and my Sig 220ST quite a bit. So much that when a go to 9mm the rounds look like .22s now. I'm not 100% sure what is the cause, since both these 45s are full size stainless, single stacks... so I'm sure it's not just the caliber. I guess I'm noticing the snappiness of the 9mm/.40 more and like the calmer .45 ACP.