Maybe it's just because I've been watching a ton of 70s stuff on netflix lately (just checked out The Conversation last night- very, very good movie), but the 70s may take the spot for me. There were tons of good directors at the peak in the 70s, and since critically loved movies were making big bucks (those were the days), studios were giving them free reign.
The 80s and 90s were both great, but a lot of this is influenced from growing up during this time.
The 00s have been pretty underrated as well. Sure, the remakes/sequels get the most pub, but that has always been the case. Big, bloated summer movies are the ones that make the big bucks. Don't blame the studios, blame the knucklehead that repeatedly go to bad movies.
but there have been have dozens of great movies this decade. Some have been big money makers (the dark knight), but most of them were smaller movies. It may take a little more time to find them, but the effort is worth it.
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