.357 magnum all the way, unless...
I would favor the .357 magnum, unless you really, really need the extra firepower for hunting or Bear protection (not that handguns are ideal for that purpose, but hard-cast, heavy .44 magnum loads can do the job *if* you can hit the mark).
.44 magnum revolvers are incredibly versatile, but I wouldn't recommend getting a .44 magnum revolver unless you reload. I don't reload, and I don't shoot my .44 magnum revolver as much as I would like to. If you need to scratch that revolver itch, I'd start with a .357 magnum and work your way up.