the Ruger Single-Six is a great little plinker
the Freedom Arms single action is hands down the best
single action
the (original) Dan Wesson's were great, but better known for 38 bullseye competition, along with the S&W k-38s of course
but "best of all world's", no contest... S&W k-frames
(and you can shoot a lot faster and reload a lot faster than those FA guys !)
6" K-17
if you are lucky, find a excellent condition one, and have the dinero, 6" K-22 Masterpiece
(never bet against somebody w/ a K-22, if it's a revolver contest, no matter what the other guy has)
if you like "smaller", 4" model 63 j-frame
(if you want to shoot 22WMR too, just buy a K-48 also, no cylinder swapping required !)
PS
nothing wrong with the more recent crop of 617s and new model 5" 63s either
can be had in six shooters