I first read The Lion, the Witch, and the Wardrobe, because it was a requirement for a class I was taking in high school. I actually really loved the book so I decided to read Prince Caspian; which I also loved, but never got around to reading the last one.
As a movie, I still loved The Lion, the Witch, and the Wardrobe. I never saw Prince Caspian, but I decided to go see the last of the trilogy.
I admit, I did not see it in 3-D, so I don't have a foundation to say whether or not it was necessary. The movie itself, though, I did not particularly love. The story line wasn't as good as the first. It seemed like a lot of it was rushed and not done as well as it could have been done. It felt like the producers had too many ideas and not enough time so they just crammed it all in there.
Maybe kids will like it, but I didn't.