I'm guessing this won't be for concealed carry?
For home defense, range fun, open carry etc... it's hard to beat a 4" .357, the ultimate do-it-all handgun for the lower 48 IMO.
I'm very satisfied with my new GP100. Very well built.
A .44 magnum would be fine also, but magnum ammo is over kill for most things and .44 special ammo is expensive and hard to find.