At the risk of opening myself up to a nasty arguement, I'm going to contend that there is--or can be--a different level (or possibly type) of emotional intensity attached to characters in books as opposed to those on screen. It's simply more work, mental and emotional and even time-wise, so that one is inclined to value the product--the assocaition with the chracters and the narriative--more highly. Becuase you're doing so much more of the world-building yourself (in your head) the narriatve world you construct is also going to be more attractive--however good the production team on a TV show or movie is, there are going to be so many more places where they can jar you out of the story (my pet bugaboo is bad green-screen work, or digital manipulation that can turn a perfectly reasonable shot into something that looks like bad green-screen work--Peter Jackson I'm looking at YOU!)

So I think dhole's contention is perfectly reasonable.