I think many of the suggestions here are great -- Fellini, Fassbinder, Wenders, etc. The New Wave is also my favorite film movement (I don't think I would be a cinema buff had I never experienced the New Wave), and one thing that you might think about is seeing films from other countries from the same years. Antonioni is a great example because his greatest films were all made in the early 1960s, just like Godard's and Truffaut's -- but an entirely different style (I, for one, happen to love his work, especially L'Avventura). It's interesting to see what other directors in other countries were doing exactly when the New Wave was taking place (and buying 8 1/2 was a good idea).