Lots of good recommendations here. I'll back what FJ540 said: get a Performance Center S&W. Not only is it more refined than the 'standard' Smith's, under your limited shooting regimen it will appreciate in value - though you may end up going a few bucks over the high end of your spending range for a used gun. New will probably be over $1000.
If you want to pick up a GP100, to me there is no other option than the Match Champion variant - it has all the bells and whistles and is Rugers attempt to break S&W's lock on competition wheelguns.
And finally, the Ruger Blackhawk - or if you think you may ever shoot cowboy action, the Ruger Vaquero. If you don't need double action - they are fine firearms and built like tanks. The Vaquero especially will hold its value well since there are always cowboy shooters looking to get equipment or upgrade from their Italian SAA clones.