I mean New York is New York. Pretty much infinite things to see and do, and I feel like every east-coaster should have at least one New York experience under their belt. It can be an overwhelming place to be for sure, but I usually have a great time. It's expensive though (though admittedly not much worse than just day-to-day-life in DC).

I find Chicago a similarly good time as New York, but I would recommend waiting for the warmer months on that one unless you know what you're getting in to. While the temperatures are currently alright, it can be brutally cold at times.

I also really like Philly and it's cheaper and quicker to get to and do stuff in.

Still haven't had a chance to get up to Boston myself.