I would say Ikiru or Au Hasard Balthazar. If I had to pick a Bergman it would probably be Wild Strawberries, it was a great movie for self reflection and encouragement "to live" in a harmonious and meaningful way; Victor Sjostrom is perhaps the equal of Takashi Shimura (the soft singing on the swing gets me every time).
Like Spiny Norman said it depends on your mood, if I'm listening to Neil Young and you ask me I'd most likely say Dead Man... Alternatively, any Wong Kar Wai and Christopher Doyle collaboration.