Sounds like you already have your first handgun? The auto has the advantage when it comes to magazine capacity, but that .357 is absolutely adequate for defensive purposes. In fact, even toning it down with +P .38 Specials instead of full-house .357s, I'd prefer it over a 9mm.
The 9mm's liability, in my experience, is FMJ ammunition. If you're willing to spend extra for dedicated defensive ammunition (typically, good hollow points), that liability can be significantly reduced. It IS very easy to shoot, though - and something that's easy to shoot often promotes fundamentally better marksmanship. A hit with a 9mm is better than a miss with a .454 Casull.
I don't have a .40, but seems every law enforcement person I know does. That's a statement in itself. But, also consider that everyone in the military who carries a pistol carries a 9mm, so it's often not a matter of choice.
The .45 (ACP) is a different animal. It doesn't have the high-velocity "whip" in its recoil like the 9mm does, but instead gets your attention with a "big bullet" shove. A double-stack .45 often gets to be too wide for many to properly grip, a single stack doesn't give you much advantage over a revolver in terms of magazine capacity. A compact .45 is the ticket for concealed carry, though. Narrow and short.
Given what you've posted, I'd probably elect the 9mm. Ammunition's more widely available (not that .40 and .45 are scarce, necessarily). If you're going to use it as a defensive gun, get some hollow points.