I'm most of the way through my second reading of Dune. First time I read it, I definitely thought it was a bit dense, but with the second pass, I'm absorbing so much more detail. I'm going to start Dan Brown's Deception Point next. Funny story behind it. I bought it for my wife over a year ago and she lost it before reading it. Two days ago, it mysteriously reappeared and she read it in a day in a half. She said I'll love it.
On a side, yet related note, just today, I pulled HP and the Sorcerer's Stone off the shelf to give to my Daughter (who just turned 6) to read. She nearly made it through the first paragraph without any help (aside from names) so I think I'm going to help her read it all.