Also, don't under estimate the effect of the room will have on your choices. You mentioned that it is 12x20. Will you be putting the speakers on the short or long wall? What else is in the room? Carpeted? Lots of windows? Any acoustic room treatments? How far away from the walls can you place the speakers? etc.
Can you post any pictures of your room in your Audiogon profile?
All of this can have a big effect. For example, if the speakers must be right up against the wall, that is going to limit your choices. (No electrostatics or Magnepans for you. )