Since it's only one password, and there's no maintenance overhead, write it down on a piece of paper, wrap it in tinfoil and seal it in an envelope. Stick the envelope in the bottom of your desk drawer. If you're afraid of losing the password in a fire simultaneously with you forgetting it, repeat for your mothers desk drawer.

Yes, if someone who knows you well physically targets you for your password, that person will likely succeed. But he would probably also succeed using this method: http://xkcd.com/538/