Though there aren't many discussions on the unranked schools there is definitely a lot better attitude overall about them than on some forums (businessweek). I think the people who spend as much time working on their GMAT and applications as the average poster on here does are probably aiming for highly ranked schools as a whole. I would bet that a lot of lurkers and people who stop by to check this out get intimidated by the talk of the top 15 schools on here and don't contribute as much as they should. Everyone can bring something to the table.
Personally I am aiming for a top school but will have a safety or two that will be second tier school. Most likely BC and/or BU which both are good programs overall but not recognized outside of the northeast region. The real reason they will be my choice of an unranked schools is location. My wife prefers to stay in the Boston area if we aren't moving for a top school, so for a happy home life that’s where it stands.