Looking at the calendar for this weekend, i would recommend Chevy Chase Ballroom ("Milonga Portenia"). Possibly the weekend intensive with Tango Mercurio/Dima, although it's not a milonga. I would stay away from Terry's, Carlos's, and Divina (Forever Dancing).
As for tomorrow, MILONGA LIBERTAD! If the weather holds, definitely go to the outdoor milonga at Freedom Plaza. It's generally extremely well attended, it's free, huge "floor," and pretty much everyone goes there. It's awesome. Not to mention there's just something special about being out under the stars in the city.