Many of the first time homebuyers I know move out within 7 years. I don't think I've stayed in a house for more than 5 years in my life. For me, the 7/1 ARM works.
Find out if the rate has any adjustment/life caps as well. If you absolutely know you are keeping the house for more than 7 years, then it might change things.
Disclosure: This is the Internet and everyone pretends to be Suzie Orman but in reality, she would probably VETO everyone on this board that wants to purchase a BMW
