Lord of the BoRings.
Lord of the Rings was just plain dull. Every single little detail in any of the three books is drawn out for pages and pages, without seeming to end. While this does lend itself well to film-making, I wasn't impressed with the movies, either. While they were decent films, sure, they're just plain not worth all the hype - not to mention three hours sitting starring at the same field from different angles and a handful of different castles. Not to mention the acting - every single time Frodo opened his mouth I wanted to throw something at the screen.
Harry Potter was much more imaginative, to be honest. And the movies had enough big names to make it worth going to see whether it was as dull and bland as LotR or not. Any movie with Robbie Coltrane or Maggie Smith has got to be decent; but a movie with both of them? I'm there.