My vote, between the two, goes for the .45ACP. I tend to favor a wheelgun, so would look for a .45 revolver (S&W 625, 17 of 22, etc.) and stick with that.
Both are great catridges to rely on, but I would opt for the .45 because of what it doesn't offer compared to the .357, namely reduced flash and report. HD use would likely be indoors, and in the dark, where the brighter flash and much louder shot-report of the .357 would be a danger of disorienting you. Plus I would worry less about over-pen and hitting something I didn't intend to with the bigger .45 over the screaming .357, but it is still a cause for concern.
If we're talking rural defense, especially against large critters, I may think differently.