I'd suggest Wicked and Avenue Q, they are both among my favorite shows and while I know some people think Wicked is overhyped if you don't mind paying the money for the tickets, I think it's definitely something worth seeing at least one. At the very least, it's very enjoyable. And Avenue Q is just hilarious and brilliant.
"If there was a Mount Rushmore for Broadway scores, "West Side Story" would be front and center. It snaps, it crackles it pops! It surges with a roar, its energy and sheer life undiminished by the years" - NYPost reviewer Elisabeth Vincentelli