Ideally, passwords for online accounts should stay stored in one spot: Your brain. But as the most forgetful among us know (if you could see me, I'm raising my hand), it's hard to keep track of every Web site registration's login and passcode.
If you've ever read an article about keeping your online identity safe, you know it's best to keep your passwords long and complicated (long strings of nonsensical numbers and letters work best) and to use different passwords for each different instance. Oh, and you have to memorize everything and never tell anyone or write it down—ever.
It's only logical that you'll end up writing down and storing a bunch of your passwords. Our advice is to keep a few mental megabytes of really important login info; like the passwords for email accounts, online banking, credit cards or utility bills; in your brain. The rest; like logins for newspaper subscriptions or casual message boards; are OK to write down and store somewhere.
So if you're writing down your passwords, where do you keep them? You could try this DIY password safe hidden inside a floppy disk or the "Top Secret Password Notepad" (pictured above), but we bet our ingenious readers have some brilliant solutions... so let 'em rip in the comments!
(Desk image from BinaryApe under license from Creative Commons, My Top-Secret Passwords Pad available for $7.50 from KnockKnock.biz)

White Enamel Flatwa...
Aside from using Firefox to remember the random sites that I don't care about anyone hacking (like this one - no offense :-) I use the program KeePass to hold all of my passwords. It encrypts my password database using the same algorithm that banks use to transfer money. Then all I have to do is remember 1 really long password (or put the password on a USB drive - the super paranoid do both)
My wife on the other hand uses the super secure method of a post-it note under her keyboard... what can you do?
You're trying to find out what my system is so you can grab my passwords and check my e-mail and bank balance... aren't you? Nice try :)
;D
I've got an excel file that is also password protected to hold the ones that are important, but that I use too infrequently to be able to remember, like my home/auto insurance site or my retirement account.