For those of you who still haven't heard from one of your top choices, you may want to give this a shot:
Last Wednesday I emailed GW asking them when I would receive a decision and they replied that I would find out in the first week of May. On Friday I sent an email to them detailing why GW was my first choice, listing various reasons including the fact that Washington was my fiance and my "dream" city. I dropped professors names and basically just begged them to let me in. Keep in mind, that I am a very borderline applicant, especially considering I applied late in the process. It may have been risky, but at this point I assumed I was about to be WL'd or worse so I figured I'd give it a shot.
Well, what do you know? Only two days later I receive an email stating that I've been accepted. It came as a complete surprise given that only a few days earlier they said I wouldn't find out for another month. In the end, I think it was my email that took me off the fence. Those of you who are still waiting on schools might want to think about implementing a similar tactic. Good luck and I hope this helps.