Planetshaker, you get 10 billion invisible internet dollars for mentioning Shane Claiborne. That was seriously like my first step to becoming a Christian; that book. No joke. Haha, so I second it.
"From Union Square to Rome" by Dorothy Day is awesome. She was a pro-abortion, Marxist, atheist woman who became Christian. She's definitely one of my heroes.
G K Chesterton's "Orthodoxy," "Heretics" and "The Everlasting Man" are all really good, too. Orthodoxy is sort of a sequel to Heretics; he answered some of the critiques that people had of "Heretics" and also talks a bit more about his own faith.