So let me swing us back to the advice that ord seeks. It might help us advise you if we knew a little about your tastes. Which ballets have you seen (by which companies) and which have you liked, which not? It will help us guide you.
I looked at NYCB's offerings for its Fall Season, and I cannot recommend highly enough the Balanchine Black and White program. It contains three acknowledged masterpieces. I don't think two of them -- The Four Temperaments and Symphony in Three Movements -- are inaccessible. (The other masterpiece is Duo Concertant.) Episodes is a little dense in some sections.
If you don't like leotard ballets or plotless ballets, then this is NOT for you. Yet.
And while it doesn't come around until the last week of Spring Season I urge you: Do not miss A Midsummer NIght's Dream. Sheer delight, wonderful choreography, costumes, story, the whole shebang!