On a more serious note, I agree with chess. Sand down as only as much as you need so that whatever remains looks uniform. You don't have to sand all the stain away unless that's what you need to do to make it look good. There should be enough thickness left to accomodate that unless the stain penetrated really deep. Oak is a hard wood so that shouldn't be the case.

BTW, Ken's turning 28 this weekend. Everyone buy him a gift cert!!