After you punish yourself thoroughly with trying to get your head around the ontological arguments for the existence of God and the ideas of The Goldilocks Principle of cosmological constants, etc., if you would like something in the vein of light relief, try The Case for God by Karen Armstrong. It's rare to say that a book will really make you see things in a different light, but Karen Armstrong is one of the few who really did that for me.
There will be no great classic theological arguments for the existence of God here - Armstrong argues that these are poison to religion. It's very hard for me to sum up her view, even though I've basically adopted it myself, and so now consider myself some sort of atheist who feels positively towards many religious traditions (a demographic of which I think I have seen some evidence for it's growth over the last few years in the positioning of some atheists distinguishing themselves apart from the Dawkins brigade). I actually feel after reading her that I could retain my atheism and practice a religious tradition at the same time, with all the benefits that accrue. I don't, but I may some day.
Anyways, if religion still interests you after old-skool theology, her book is at least a different take on what it's all about, and how often do you really get something different? Never mind one that can change your mind.