The recommended order, as Lewis wrote them:
1-
The Lion, the Witch and the Wardrobe
2-
Prince Caspian
3-
The Voyage of the Dawn Treader
4-
The Silver Chair
5-
The Horse and His Boy
6-
The Magician's Nephew
7-
The Last Battle
http://www.alexlibris.com/rev_narnia.asp
"Some would call the seven Chronicles of Narnia, by the master story-teller, C. S. Lewis, the crown jewels of children's literature. Full of adventure, suspense, surprise, -- and much more -- they appeal to children of all ages -- from 8 to 108. I am 72. I feel compelled to set straight a misconception about the order for reading these marvelous adventures. Some recommend changing the order. They have even been so numbered by a publisher. I think this is a grave mistake. They should be read in the order in which they were written for this reason: *The Lion, the Witch and the Wardrobe* was the first and is the foundation stone. It introduces and undergirds the series in a way that none of the others could possibly do -- and makes them all unforgettable. It was followed in order by *Prince Caspian*, *The Voyage of the Dawn Treader*, *The Silver Chair*, *The Horse and His Boy*, *The Magician's Nephew*, and *The Last Battle* -- which is the superb climax. *The Magician's Nephew*, the sixth, goes back to the dawn of time. To read this strange tale first, as some recommend -- with no reason given other than chronology -- might for some be to miss the rest of the adventures of Narnia altogether for lack of interest. And what a loss that would be! It would most surely be to miss the richness of all those poignant aha's as you discover, for example, the circumstances of how those extraordinary things you already know and love -- such as the wardrobe, or the lamppost standing alone in the middle of the wood -- came into being, as well as having prophetic insight as to the roles those things would one day play. When you read it next to last -- bringing to it the wealth of the other stories -- it, too, is a fascinating and unforgettablre adventure."