My taste runs to comedy, so probably joint top are 'The Life of Brian (arguably the best comedy ever made) and 'The Blues Brothers' - not as funny but great music. I also quite liked 'Spinal Tap' and it's little known follow-up film 'A Mighty Wind'. Finally not forgetting 'Blazing Saddles'.
However I loved 'A Local Hero' and, for some strange reason, 'The Searchers' even though I'm not really a Western fan and most certainly not a John Wayne fan.
Rob