properly invested you could be very comfortable with that kind of cash. don't think it woudl be enough to retire on, but you coudl certainly ease off of the daily grind a bit.
650k in an ing direct orange savings(paying 3.5% currently) is still 22.5k a year. not a bad income for jsut continuing to breath. add a part time job or even a barely full time job doing something fun and you can easily make another 20k a year.
that is plenty of cash for a double wide in florida and money left over for toys
