I was certainly tempted with the 327 Federal. But in the end, I didn't go with it. Part of the decision was the fact that I never saw any ammunition for it in at the gunshop. But as you can see with the next two calibers, they aren't so common either.
My "oddball calibers" are the 41 mag and 480 Ruger. I like both of them. I have no problem defending either of them.