magictodo123 said: "I'm trying not to be such a Broadway snob and explore the offerings at places like Second Stage and other off-Broadway locations. Anyone have any predictions on some of those must see shows?"
As others have noted (theater groups and individual theaters):
The Atlantic, Signature Theater, Roundabout, 2nd Stage, Primary Stages, Playwrights Horizon, The Public Theater, NY Theater Workshop (NYTW) and anything at Lucille Lortel, Barrow Street, Cherry Lane, BAM (Brooklyn), Theater for a New Audience (Brooklyn), 59E59, Lara Pels, Irish Repertory Theater.
There are plenty of very rich theater to be seen off-Broadway. I see a handful of off-Broadway in addition to hitting most of the Broadway offerings on my 2-3 trips a year to NYC. A good amount of productions make a transfer to Broadway houses, and you get to see the next hot ticket early on and for lesser prices (but you also sometimes get it earlier in the development and what transfers is not quite what you saw).