I'm a huge fan of lever-guns. I like mine in .45 long colt, but they tend to be very expensive to feed. Not so much a problem if you reload.
I'll add my vote to one in either .357 (cheapest ammo), .44 (best factory ammo performance), or .45 LC (for the cowboy in all of us.)
“There are three reasons to own a gun. To protect yourself and your family, to hunt dangerous and delicious animals, and to keep the King of England out of your face.” - Krusty the Clown