From an energy standpoint, common fridges are the better option. Because compact refrigerators are so small, manufacturers often maximize interior space by reducing the amount of space given to insulation. As a result, mini fridges are less energy-efficient per cubic foot than full-size fridges. So, if you can work out the details of ensuring that your dorm mates can reasonably share a larger fridge (such as agreeing to eat only their own leftover pizza) then by all means share the space! For the most energy savings, have your school purchasing agent look for an ENERGY STAR® labeled refrigerator. You can find information about available rebates at the Rebate Center in the Residential section of Efficiency Vermont.