IMo, the best film of the colorless days was Inherit the Wind. The movie is personal favorite 60s movies, and I believe one of the most important films of all time (Albeit it's based on a play.) It saddens me to think how the Evolution Vs. Creation argument in this film is more relevant today. This film taught those Bible humpers a lesson, (Don't get me wrong, I'm a christian, but not a crazy fundamentalist.) Spencer Tracy, Gene Kelly, and Frederic March all had great performances.
Pretty much anything with Gary Cooper or Jimmy Stewart. I love those guys. If I had to pick one, I'd probably pick Sergeant York. Despite it's Strong Christian Overtones, it has the bonus of being pretty kick ass.