If you're just looking to catalog DVDs and/or Blu-rays you own, I'd recommend DVD Aficionado. http://www.dvdaf.com
You can search by director, some actors, studio/publisher and many other categories. You can make notes about your own personal copy, and you can make as many lists as you can imagine. You cannot however edit an entry and update information ala ComicBookDB.http://www.TVTome.com
allows for editing entries, but I don't know that it has a collection aspect to it. You can put a show on your watchlist or favorite it, but not on a episode level if you need that.http://www.IMDB.com
allows for editing entries, but most things need approval after submission. And you can make a MyMovies list, and even detail it by an episode by episode basis. It isn't very user friendly in its current state however. You have to add everything to a catchall watchlist first, and then you can move those entries to other self made lists if you choose to.