I've always thought of these two film trilogies as a sort of twin pairing:
The Matrix trilogy - Masterpieces of science fiction cinema.
LOTR trilogy - Masterpieces of high fantasy cinema.
Since I'm going to delve into the Matrix films in depth later on I won't waste text talking about them here.
Like any true Tolkien fan, I read the books long before the Peter Jackson films started development. And as a fan, I must say that Jackson did an excellent job with the material. Too often you get film adaptations that are mediocre at best. "The book was better" is a common mantra when it comes to dealing with those types of films. In this case I was supremely pleased to see that they weren't just some cash grab endeavour. I mean, look at that! Three books => three movies. You remember when The Fellowship of the Ring  came out and everyone noted that it was a whopping three hours long? But then you went and saw it and didn't even notice? You came out of the theater and the sky was black and you thought to yourself, "Whoa, its been three hours?" That was me.
I have no doubt that if it were to be released today the studio would have decided to cut it in half and double their ticket sales.
That's not a dig at Harry Potter and the Deathly Hallows, by the way. Sometimes its beneficial to have two movies rather than try to cram everything into one package.
I love The Matrix for making me think. The LOTR series doesn't have all those metaphysics and ontology issues. What it did was make me feel and make me love these characters. The movies did the same.
Sometimes I feel a sadness for Tolkien fans who died before they ever saw these movies. They missed out on something beautiful.