I don't buy the imagination argument.
Of course imagination is based on what's supplied, but just like there's good descriptions, there's good screenplay in a movie. The thing is, an awesome scene still does not match an awesome chapter in a book, not for me anyway. Because my imagination is limitless, I don't need to worry about the explosion being too big or too flashy.
When I read the text, I unconsciously adapt what I am reading to better suit my own preference. In a way I will corrupt the vision the reader had, but to me, that's a bonus. When I read a description of a dragon, I'll of course picture it in my mind as it is described, but I'll change minor things in my mental image, subconsciously, to make it perfect. Whereas a dragon in the movies usually fails to please me because the graphical designer for the dragon no doubt made one or many fatal mistakes on how _I_ percieve a dragon. That impact is much less when my imagination gets to paint it for me.