G.K. Chesterton is another classic Christian author.
If you like historical fiction, try Paul Maier and The Flames of Rome or A Skeleton in God's Closet. Maier was a professor of ancient history, so he's better at history than prose, but they're still a fun read.
However, though I fit the conservative label, I don't always stick strictly to reading works only by those I agree with. For example, my favorite Christian novel of all time is The Maiden's Bequest by George MacDonald. MacDonald's ideas were odd, and it comes out in his other books, but in The Maiden's Bequest he restrains himself and wrote a masterpiece ... or at least I think so.
Then, two other books with strong spiritual themes that wrestle with Christianity are Ahab's Wife and The Poisonwood Bible. Having had struggles of my own, I could really relate to those books. SPOILER ALERT: don't expect a conventional ending. Regardless of that, I enjoyed them. It helped me better articulate why I didn't make the same choices as the characters in those books.