Something like Lastpass is also a good way to do it, if you need to reset all your passwords, lastpass can change a lot of the more popular ones for you.
+1 for lastpass.
Otherwise, I'd use paper, not a spread sheet. It's really unlikely that someone breaking into your home will be a hacker, and someone breaking into your computer will be. Apparently written records of passwords a very secure.
(I once had a work system insist that I create yet another password, mixture of upper and lower case letters, numbers, special characters that was not one of the last 8 passwords I had. I ran out of passwords i could remember that met their requirements, so I wrote it on a post it and put it in my top drawer. It was a sort of f*ck you to their idiotic security)