Cafe Du Monde.
Absolutely worth the hype.
It was literally the first place we went when we arrived in NOLA. A well-appreciated tip from a friend who attended college in New Orleans is to order the hot chocolate and dip the beignets in the hot chocolate. Like any great New Orleans trip, we ate and drank constantly.
New Orleans is unique in that I felt like I was in a different country while I was there. Many Midwestern and Southern cities are quite similar with slight differences in cuisine and music, but NOLA is it's own animal. From the architecture and cuisine to the overall casualness of the inhabitants, New Orleans sets itself apart from just about any American city.