I'm not sure what I can say about this that hasn't already been said. It's an epic masterpiece. Tolkien's language is poetic and his voice fits the mythic nature of the story.
For example, Tolkien begins the book with what's basically a big info dump about hobbit history and culture. It's nothing but telling with little to no showing. As I waded through it, I kept hearing a nagging voice in the back of my head telling me, "Show, don't tell!"
The pacing of the first book also could have used some tightening up. The pace was way too slow, seeing as the story ranged over several years, from Bilbo's "eleventy-first" birthday up until the day when Frodo left the Shire for Mordor. This first book unbalances the entire story, since we sprint through those years, while the other two books seem to last just a month or two.
Recently someone on The Late Nite Jengajam commented that Peter Jackson did the right thing in the way he edited the story to adapt it into the three movies. I can't say for sure if The Lord of the Rings would have been as popular or beloved if it had been edited to suit modern tastes. Who knows? But I can say this with confidence: if you haven't taken this journey through Middle Earth yet, you should.