There are so many good books out there, it’s hard to give less than 100 suggestions. I'll give you lots of suggestions, but...
Here’s my very first suggestion: read the Bible.
Before you read what people think about God, see what his words says about himself.
Great Books to Read List (2016)
If you read every book on this list you would level up.
Pretty much any book by C.S. Lewis, A.W. Tozer, J.I. Packer, Hank Hanegraaff, John Piper, Gary Habermas, Dallas Willard, or N.T. Wright, and anyone at Reasons to Believe would be good. That doesn’t mean I agree with them on all points – I definitely don’t. But, they are relatively deep thinkers, solid theologians, and orthodox.
Great Books to Read 2
Once you finish list number 1, here are some more books to digest!