Well i just calculated some stuff and it seems i would only make about 4 cents per day with 2 block erupters lol.
Your BE should run for 330 MH/s, and thus you would be able to get a few cents a day (before electricity cost).
With say a raspberry pi block erupter setup or maybe in the future with one of these http://www.butterflylabs.com/monarch/
Just a friendly reminder, BFL has a very bad record in the past in keeping its delivery schedule of the pre-order units. You should be prepared to get your hardware months or 1+ year late, or should better stay away from BFL.
