Don't discount the Ruger Single Six/Ten just because you read some "expert" say they aren't accurate because of the bore being slightly oversized for WMR. I have two single Sixes, and a Single Ten, and they will put every round into a 2" target at 25 yards. My Single Ten is the most accurate of my three, and also the most sensitive to different ammo types. It will "One Ragged Hole" all day long at 15 yards with its favorite ammo.
The older Smiths are beautiful, and exceptionally well made, and I agree they are probably the most accurate, but they also command a premium price. IMHO, most shooters wont be able to shoot any better with one of the Smiths, as opposed to the Ruger.