Mama always said, pretty is as pretty does ...
I guess the best looking .357 will be a Python -- an older one, with the "Royal Blue" finish and nice wooden stocks. Personally, I'd go for a six-incher.
The Pythons hold their value pretty well, which helps justify the purchase of a "looker" over a "shooter."
Next on the list would be an older Smith, perhaps a well-preserved Model 29.
Go used, and take your time.
Personally, I have an irrational fondness for the Smith "Combat Masterpieces" in .38 Special (aka Models 15, 67). Some of the older, pinned barreled examples are surprisingly good looking, especially when fitted with nice, aftermarket wooden stocks. And they're more agreeable to my budget than the Pythons!
Of course, these guns are SHOOTERS, and I've never met anyone else who shares my opinion about their looks, so ...