What a hard choice to make!
If the question was "You do not own any revolvers at all, and you can only buy one current production revolver, what would it be?"
I Would have to say.... a 4" .357 Mag in either a Stainless Ruger GP100, a stainless S&W 686 (6-shot) or a S&W 586 (because S&W blue guns are purtty). Most likely I would pick the Gp100 because I like Ruger revolvers. So, I say a 4" GP100.
If the question was " You can only get one more current production revolver to add to the revolvers you already own, which would it be?"
I would have to say I most likely would go with a stainless Ruger Blackhawk 9mm/.357 convertible with the long 6.57" barrel. Great looking, well made, can shoot three different calibers, very accurate and I think its really cool. So, that would be my choice under the second question format.