There were no ugly cars made by the American auto industry in '57. Every make and model was a beautiful car; instant classics spread all across the board. That said, in my opinion, the Chrysler cars of 1957 have the GM and Ford cars beat. Long, low, sweeping, graceful, dramatic... in that year, only the Cadillacs and Continentals have timeless style to match the Mopars. Yep, I'm jaded.
57 was a wonderful year for all the car companies but Pontiacs have always been my favorites. I'm going to go to central Nebraska to look at a 57 chieftain hardtop after deer hunting season. I already have a '59, 389 motor, a stick setup [flywheel, bellhousing correct starter, clutch etc] and a Muncie 4 speed for it. We'll see.
I've never had a 57 Buick but they have the absolute best rear wheel well and side trim. The car just nails it, dam near sexy to say the least.