The Two Towers is my favorite movie out of Peter Jackson's trilogy so I was disappointed that it isn't my favorite book so far.  I think it's because I like the rest of the Fellowship's adventures more than Frodo and Sam.  The first half of the book follows Aragorn, Legolas, and Gimli as they search for Merry and Pippin.  The second half focuses solely on Frodo and Sam's journey.  I like how the movie is structured more because it switches between the two story lines.