I think there is a great deal of value in reading the works of other faiths.  What have you read from other faiths or beliefs that you enjoyed?  This not a thread to say, "I read XYZ and it was ridiculous."  Only list what you read and would reccomend.

My list:
The Meditations of Marcus Aurelius
The Golden Sayings of Epictetus
The Analects of Confucious
ETA  These three I like for the same reason.  They have a lot of great No-so-common sense wisdom and pithy statements.
Zen and the Art of Motorcycle Maintenance an excellent book on living your faith

Machiavelli: The Prince
Nietzsche: Beyond Good and Evil

Many, many more.

Yeah. St. Augustine.

I've never read anything in Nietzche that I've appreciated except, "Women have many problems, and the solution to all of them is pregnancy."

Meditations Aurelius
De constantibus  - Seneca
Zen and the Art...
Education of Cyrus  - Xenophon
Against Christianity  - Julian