I do this, but I leave it on a sticky note behind a piece of furniture, or in a file folder related to the account. But I don't put the actual password on; rather, my passwords consist of a "leetspeak" word, and the sticky note has a fairly simple hint one to two degrees out-- but if you even guessed the answer, you would still have to figure out the numbers in combination.

For example, if I used 5p0ng3b0b, I would write "who lives in a pineapple under the sea?" or "Patrick"