OP already nixed the idea of a semi auto, so a CZ or Glock is off the table.
It looks like the Single Six or Single Ten is the way I'm leaning. I also love that it will be a gun I can pass down for generations
Very true/wise outlook.
Quality always remains long after the initial sting of the purchase price has passed - is what they say.
Single sixes aren't rare on the used market, but, considering the huge numbers of them sold each year....most people hang onto them for a long time.
The S&W mod 17 and 18 are similar. They will usually be at the upper limit of your price range ($500).
Another dark horse in the D/A market is a used Dan Wesson.
Every once in a great while, one pops up for an affordable price.
Dan's have been rediscovered in recent years though and prices on older used one's have shot up.
If you run across one in your looking, $300 for one in like very good to excellent condition that has the barrel wrench and feeler gauge is a steal.
Dan's use a D/A trigger system with an extremely similar feel to that of a Ruger, only (usually) much smoother and more "refined".