I found the reception place of my dreams which is a historic mansion with tons of character between its 7 rooms on the main floor, all at our disposal.  We will have about 150 in attendance.  If we do a seated dinner, we will be packed in because of the seperate rooms, but we'd fit.  I would prefer to do a standing reception with a buffet and/or stations setting random sized tables and chairs around the house and outside.  Do you feel it is necessary to have a seat at a table for every guest?