There are many other great books as well, there are also many not-so-great ones. I simply wanted to include some of the strongest that I have read, and I hope this can be beneficial...
The Bible (seriously) - It's easy to let Christian books take the place of the Word of God. From someone who spent years reading more Christian literature than Scripture, don't make that mistake. My highest recommendations if you are looking for a Bible are the ESV Study Bible, or the Apologetics Study Bible (Holman Translation).

Knowing God - J.I. Packer. If you are ready for a really rich read on God, this is an incredible book. Packer is a theologian, and his book is not incredibly difficult, but it is so rich that it really is read pretty slowly. Packer is able to say what so many have taken multiple volumes to speak about. Every Christian should give this book a read at some point.

The Screwtape Letters - C.S. Lewis. This list of course would not be complete without highlighting the accomplishments of C.S. Lewis. This is one of his most popular works, and he has a gift for highlighting things about God that we never considered. While I don't agree with everything that Lewis writes, some other great books by him are Mere Christianity, The Chronicles of Narnia, Out of the Silent Planet, and Perelandra.

Pilgrim's Progress - John Bunyan (Get an updated version, either Warren Weirsbe's or Cheryl Ford's). This has been the most influential book for Christians in the English language in history, and there is good reason. Bunyan himself was an incredible man with a passion for true salvation and Scriptural truth. This book helps a Christian to understand many Biblical truths in a really practical way. This book is easy and rich and deep. Also Grace Abounding to the Chief of Sinners is a famous work by Bunyan.

Don't Waste Your Life - John Piper. Be ready to be jostled, maybe even offended, but also to be motivated to not waste what God has given us on this earth. This book will aid in propelling you to savoring Christ in the Word of God. Other great books by John Piper include Desiring God, and God is the Gospel.

Chasing Daylight - Erwin McManus. This book was an incredibly great surprise, and it is different than any other book on this list. It is the easiest to read, but one of the most compelling. I highly encourage anyone feeling lazy in their faith to read this.

The Jesus I Never Knew - Philip Yancey. This is a great book about the Jesus we so often assume we know all about. It is easy to read, and is a rediscovery of Christ worth reading.

If You're Looking for Something to Read...
Jonathan Recommends: