I've been using this free site, listal, to list my dvds, books, music and games. You can track what you have lent to people, or borrowed from other listal members, or what you want to buy and so forth.
If you join up, add me as a friend. And if you really want to, you can share your list with other people online, eg. http://damienmason.listal.com/ (it's incomplete, I still need to add more books and music)
It's very cool. And free. Did i mention free?