I own the Multimedia CD-ROM version of this that includes movie clips from the 1978 film. It was a fantastic game, and is actually where my avatar comes from.
I remember playing this game when it first came out and was blown away by the sound, music, and graphics. I imagine the CD-ROM version will never become available on GOG, but it is a game that deserves to be shared with the masses.
There is a lot of interesting tidbits about the development of the game and how the Tolkien estate wanted the game to focus more on exploration and less on violence. Hence, why there are some battles and pivotal scenes where you win by utilizing "words of power" (such as Elbereth or Luthien), or you have to run away.
This game covers a lot of areas that were not covered in the films, but was covered in the books. You even get to meet Tom Bombadil!
Overall, I really enjoyed the game, and wished Interplay could have finished the trilogy (we only received Volume I and II), as these games had a great mix of exploration, puzzle-solving, combat, and adventure.
One thing to note, this game is not the same as the one that was released on the SNES, as that was more action focused. While this is more adventure-RPG.