I voted for Fear and Loathing but I must say; no other drug movie fucked with my head more than Requiem for a Dream. Years ago I had a little depression going on over an old fling cheating on me. Well I had to watch Requiem for a Dream for a college class and after I saw it I felt like shit for days. I believe much had to do with the film score, as well as the ending scenes where it demonstrated the complete degradation of all the cast members. The parallel seemed to hit a nerve with my own state of mind, albeit for different reasons. My point being, for cinematic enjoyment I go for Fear and Loathing, but the symbolism and emotion in Requiem is much more potent and is brilliantly written.