Fellini is one of cinemas most original and visionary film makers. He changed a lot over the length of his career and maybe didn't end on a high note, but he made several influential films including what many critics feel is the best movie about a "movie" file, 8 1/2.
Other notable films are I Vitelloni, La Strada, La Dolce Vita, and Amarcord to name just a few in a career that spanned nearly 40 years. My personal favorite is the already mentioned 8 1/2, but I must admit that I haven't seen all of his films yet. I look forward to getting to the ones I missed soon.