St. Thomas Aquinas came up with five very good "proofs" of the existence of some sort of a god. In skimming this thread, I get the impression that many of you think that if you find a problem with the Christian definition of God there is no god. Aquinas was very clever in applying almost no doctrine to his proofs, making it more universal.
Here is a link to a summary of this text.
http://members.aol.com/plweiss1/aquinas.htm