The title says it all: what are your favorite and least favorite non-Orthodox books that you've read?
My favorites would be:
- G.K. Chesterton, Orthodoxy: The Romance of Faith (Don't always agree, but makes you think and has tremendous wit)
 - C.S. Lewis, The Screwtape Letters (very insightful, and not altogether unorthodox)
 - Luke Timothy Johnson, The Anchor Bible: The Letter of James (a good commentary)
 
My least favorites would be:
- Bob Enyart, The Plot (manuscript of a hyper-dispensationalist, open theist--to mention just a couple strange beliefs)
 - Bruce Chilton, Rabbi Jesus: An Intimate Biography (claims to be scholarly and objective, but reads more like a religious novel)
 - Basil Pennington, Centering Prayer: Renewing an Ancient Christian Prayer Form (by a trappist monk apparently following along the same spiritual path Thomas Merton did)