Ever heard of the ancient Greek philosophers? And I've mentioned them just for starters.
ippy
Rather bad generalisation if you want them to support your case. Two of the most famous (Socrates and his promulgator Plato) believed in a spiritual realm of ideal forms, of which the items in the material world were only a representation. Plato in Timaeus also speaks quite directly of a divine demiurge. Not to mention that both of them believed in 'souls' - an idea which greatly influenced the development of Christianity.
Of course there were others who were purely materialist. They're all worth reading, and when you've read them, you can make up your mind.
Homer's Odyssey is also worth reading, even though it deals with myths and gods. It remains a classic of world literature. Honestly, you can get something out of it without wondering that you'll end up believing in the gods of ancient Greece. What are you afraid of?
It's also possible to read the bible without necessarily ending up a confirmed believer - after all, many types of literature are contained in it - some of it is even provable history (though not much about Jesus is so provable, nor most of the very early part of the OT).