Webster's Dictionary defines literature as:

writings in prose or verse; especially : writings having excellence of form or expression and expressing ideas of permanent or universal interest

What does or does not constitute excellence of form is a matter of opinion. For myself, I have read many of the 'classics', and yet I consider all but a few of them to be absolute crap. Dickens in particular makes me cringe, as does Dostoyevsky. I would rather read the driest commentary by Tolkien than the greatest works of either of these authors.