He did almost nothing for the story, admittedly. He was just there to add mystery and I loved his parts. He always spoke in rhyming song that could defeat anything in His Land (why is it his land? So wonderfully mysterious!). I like how the Elves mentioned how The Ring would be perfectly safe forever were it given to Tom, as anything that came to His Land could be defeated with his songs, but someone says summat about him just throwing it away as a useless trinket.
Wow I went on there.

Tiger! Tiger! by Alfred Bester is amazing. As is Flowers for Algernon. The only book to have ever made me cry.