I get questions like "What is the svn address again" or "What was my password" all the time.
You could write them all down somewhere on paper. But copy-and-pasting them is so much easier and faster.
So we end up putting them on the hard drive.
Use encrypted storage files
With truecrypt (www.truecrypt.org/), for example, you can create a container file that includes itself in the system as an own partition (with any letter you chose like Z:/). But any other software will do, as well.
There you can safely store all the passwords, account infos etc in plain files at one single location. easy to find, easy to update.