8. (TIE) An asking price at this level can only stand for something extraordinary, and that's exactly the word for this 312-acre oceanfront property on Martha's Vineyard.
Price: $100 million
The stately main house gives way to more unique attractions: A massive expanse of private beach on the Atlantic Ocean, a 35-acre pond, miles of walking and equestrian trails, and plenty of room for more to be built.