I think you nailed it, up until the last 3; I've never seen Spinal Tap, though, so I'll give you the benefit of the doubt. The 3 different ones I chose were Blazing Saddles, Dr. Strangelove and The Blues Brothers (kinda stupid, I know, but I love it -- plus it's the best musical ever.)
Also, I meant to vote for Life of Brian but chose Spinal Tap instead. Yeah, I know, it's Monty Python's sellout supposedly, but it's still a marvelously-made film, and frankly it works better than the anarchism of Holy Grail. I just don't feel like the anarcho-comedy really translated to the big screen very well.
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