A recent Harvard study found that it matters less what you say during an interview then how you say it.
The study (click here for an interview with the authors and to purchase a copy of the study), showed a video of a political debate where the subject answered questions in a series of videos. In the first video, the individual answered the question directly and well; by the third video, he answered the question directly, but inarticulately.
The response from the study showed that people liked the individual answering the question less when he did so inarticulately. Perhaps a good tip for your next job interview is not necessarily to know all the answers, but know how to answer the questions.