Attention U.S. TCM Subscribers: Journeying to a completely different cinematic landscape (from my previous endorsement) there's Preston Sturges' masterpiece Sullivan's Travels, a prior Blu-ray recommendation here:
This movie is so good and important I had to buy it when Criterion put it out on Blu-ray. As TCM says, I think it's one of the "Essentials." If you've never seen it, SEE IT.