Patrick Kurp quotes H. L. Mencken:
“There are people who read too much: the bibliobibuli. I know some who are who are constantly drunk on books, as other men are drunk on whiskey or religion. They wander through the most diverting and stimulating of worlds in a haze, seeing nothing and hearing nothing.”
Apparently Mencken himself coined the word, bibliobiduli. I like the word, but note that some bibulous readers read to improve their seeing and hearing.