If you've got a Glock or S@W the Ke-tec sub-2000 might be worth a look. The fold-up feature is nice for a bug out un. They are also pretty cheap, about $400. Whether they are any good or not, I don't know, but the fact it uses Glock mags (reliable, common as dirt, and with the thirty rounder available) is a huge plus.
FQ13
PS that said, for a general utility multi tasker, its hard to beat a .357 carbine (although I do prefer .44 mag if I were starting from scratch). You're not. For SD, the 10 odd rounds in the tube are all you're likely to fire anyway and it will fire pretty fast with practice. It will also work for hunting.