It's not surprising that recent college grads want to live in bustling urban areas. What's surprising is how much space they are willing to give up these days to buy condominiums in super-cool city locations. In an effort to keep prices down for cost-conscious young buyers, new apartment buildings around the country are being built with an average unit size of around 500 square feet, reports MSNBC.com. But different cities have different notions of "small": In Portland, Ore., a small condo is around 520 square feet; in San Francisco, the 98-unit Cubix building in the super-hip SOMA neighborhood is selling condos ranging from 250 to 350 square feet.