I work professionally in the field of Identity and Access Management, so I'm going to let you in on the secret to keeping your home passwords safe and secure...
WRITE THEM DOWN
The biggest risk you as a home user has is being phished / keylogged / brute forced (tabled). Neither of these involves someone rifling through your bookshelf for a notebook with passwords on it...
By writing them down (and keeping them someplace that doesn't scream "steal me" at the same time as someone's nicking your LCD) you will enable yourself to use nice strong passwords that are not dictionary words.
It also makes it really hard to forget your passwords
If you travel a lot, consider the slightly less secure software solutions (such as KeePassX).
In short, your biggest risk as a home user are REMOTE attacks, these don't involve physical access to your house. If you save the passwords on your computer they are less secure than if you just wrote them down and kept them someplace obscure.