Preferably not New York because people have said that's very expensive, but it might be nice to put it somewhere near Canada, so that some of us can trickle over the border and join in. I noticed quite a concentration of users in Toronto, so if it were somewhere near the border, a decent amount of Canadian attendance might be feasible.
And in the future, (very possibly the far future, which is fine) it would be nice if this came to other countries as well. I know it's been stated multiple times that people outside the US are free to organize their own meetups, but I find it rather unlikely that anything like this could ever get off the ground without the backing of mangadex staff. It would feel less official and I think that would make people feel more wary of it. (Side-note: if there's actually any interest, I'd be glad to help organize a meetup at the Montreal otakuthon.)