One of the things I really loved about the books, having reread them recently, is the degree of interaction among all the members of the Fellowship. The movies don't really have the time or the space to capture this, but over the course of the three books all of the Fellowship gets a pretty decent interaction with each other. The movies break them up into bunches: Merry and Pippin, Aragorn/Legolas/Gimil, Boromir and Aragorn, Frodo and Gandalf, Legolas and Gimli, etc.. These divisions are also present in the books, but Tolkien loves to escape them even as he sets them up, so you'll have great scenes like the one in the wreckage of Isengard where Aragorn, Legolas, Gimli, Merry, and Pippin are all chilling and talking equally amongst themselves. The Fellowship all really feel like a gang of friends, who have grown closer after everything they've endured.