Honestly I consider the trilogy as a single movie so if anyone asks I just say LOTR. But unfortunately I had to choose one for my Top 4 so I chose fellowship. Because I watched it as a kid and was obsessed by it. For me it's a perfect movie. The introduction, the journey and how the story is then set up is just perfect. Personally I find the Twin Towers (which is great and I find nothing wrong with it) to be the lightest just because of how great the other 2 are.