Games About Books???

Hello all you gamers! What do you think about games that are based on books? I am thinking about things like Rainbow Six. Do you think that these are good for the industry or bad? And while we're at it...what do think about movies based on games? Many times I find myself thinking...WOW! That game would be a GREAT title for a new movie....but most of the video game based movies I've seen just aren't as good. Do you think there is something related to the interactive nature of a video game that makes its plot compelling on a computer or console, but not so much on a movie screen? I'm not sure. What are your thoughts?