I'd kind of like to get a big bore single action, like a BFR in .500 JRH or something to that effect. But for me it's totally impractical, it's big and powerful but it won't do anything in my neck of the woods that my .45 Colt, loaded warmly, won't do.
On occasion I still think about picking up a Blackhawk in .41 Mag, and while I think it makes a lot more practical sense than a .500 anything, since I have the .45 Colt Bisley I'm not so sure I need it, but then again, if we only bought guns we need then we'd only own one or two, and what fun is that?