I still find it astounding that some folks haven't read Lord of the Rings. Then again, the book is huge, and I am sort of a fantasy geek (and don't ask about all the classics I've never read). Still, if you're on the edge, maybe I can help push you over.
1. Nazgûl. The undead servants of Mordor. They never sleep, never die, and never stop coming. They're kinda like Dementors, but they aren't scared of a silly glowing stag. And they ride dragons.
2. Gandalf. Every awesome wizard and mentor character you've ever read about was based on this guy. Dumbledore was killed by a silly curse. It took a fricking balrog to take Gandalf down. (And even then...)
3. Frodo and Sam. Bet you didn't know this was a buddy story. Frodo and Sam are hardcore. Think Naruto's tough? These guys walked into hell with the devil's wedding ring (he really wanted his ring back, too).
4. Maps. Harry Potter doesn't have 'em. Nuff said.
5. Middle Earth. Beautiful, even if all you've got are Tolkien's words. I'm pretty sure I'd die there, but I want to visit just the same.
So what's your favorite thing about Lord of the Rings?