I can't speak for BU, but I can say that if you are in the top 1/3 at Emory, you should be able to get a job with a big firm in NYC provided you don't turn people off when you interview. Ditto for Fordham. Conversely, if you are thinking about Southeast, more firms have experience with Emory grads than Fordham grads (as most choose to stay in NY). While I know some people here at Emory that are going to Boston, if you are thinking about Boston, BU is probably a safer bet.
I think there is a misconception on this board that if you go to Emory, you are going to be stuck in the Southeast. That is just plain not true. I'm going to the west coast this summer (I have zero ties there), and many, many of my classmates are going to NYC.
I would look at which one is cheaper and which one you like the best if you get a chance to visit.