The Artful Dodger wrote:LOTR for me. I enjoyed the books and films equally, but prefer the books.
Potter for me for specifically this reason. The LOTR books are tremendously overrated. They were ground breaking and pretty much started an entire genre but on their own they are good but not great. I couldn't read them a second time even though I tried.
Also the movies were all oscar nominated but I found the last one very disappointing. I love the movies and can watch the Battle of Helm's Deep all day (I think that I may have) but these were not oscar-worthy pics.
Potter on the other hand are incredibly written stories. They are stand-alone and as a series, better written than LOTr and withstand numerous readings. They movies are meh but I picked Potter for the books.