Size not too big, not too small.
Most sitting at culture rich, economically vibrant cities or close to them
A lot of events (cultural, arts, sports) & programs (travel, international, connections to power sources)
Top faculty
Targets for recruiting by top employers
Research opportunities
Personal interaction - Most top private schools have student to faculty ratio at 6-8 to 1, MIT has 3:1 (basically there are more top research opportunities than the available students to fill them)