In Omo's comments, I read things like:

Like Omo, my manga, anime-related novels (and other books), and anime-related CD purchases come to about 2.5 times my DVD purchases (I don’t buy figures, really, but I do buy character art).

Although I know it to be a conventional wisdom (see Yohurt in Spaceballs), personally I do not feel an urge to buy themed goods most of the time. All I have is two sets of Azumanga manga (ADV and Dengeki), Azumanga artbooks, and Rocket Girls light novel. I suppose I'm out of touch with the soul of an average fan...