If you look up at DaveF's post, you'll realise he's making quite a funny joke about why Tolkien was not a huge Narnia fanMatthew, Thanks clarifying my (poor) attempt at humor. I enjoy and respect both Lewis and Tolkien immensely.
"The Voyage of the Dawn Treader" used to be my favorite book of the series. I loved its imagination and variation. The Dufflepuds still amuse me and the tale of Edmund and the Dragon is a wonderful parable.
But I re-read the series every few years, and after reading them last year, I think I now favor "The Silver Chair" the most. It is perhaps the best story of the bunch. And I adore and identify with Puddleglum. Coming close is "The Horse and his Boy", as an excellent story and perhaps hinting at the narrative style of "Esther" (in the Old Testament); also "Prince Caspian" for its strong story and effective use of flashback to tell two halves of the same story until they are brought together.
I hope that the Narnia movies are given at least as much respect as the LOTR trilogy were. Done properly, these could be LOTR meets the best family movies Disney ever did. They have struggle and adventure for the youth and metaphor and spiritual depth for the mature.
And if they are poor, I will send Reepicheep in to reclaim their honor