I just saw A Clockwork Orange for the first time. I've seen a few of the iconic scenes before but never watched the movie in full. Holy moly! Crazy movie. The style is so iconic and I'm starting to think I better watch Dr. Strangelove again now that I've had more of an introduction to Kubrick's style (I just saw 2001 last week too). The main actor who plays Alex is astoundingly good, and the cockney Britishy dialect the gang speaks is ultra-weird and fun.
It has an interesting 1984-ish feel too it and exhibits some great dark humour. Some of the particularly violent scenes must have been *very* graphic by 1971 standards. (Apparently this has since been "downgraded" to an R rating...)
Like Requiem For A Dream, this is by no means a pleasant cinematic romp - it throws some brutal questions at you about society and takes an incredibly cynical view of family, government, relationships.... but the intensity of the message is so strong and the style of the film is so iconic (there, I used that word again!) that it's clear why it has landed comfortably in the "film classics" department.