Sioraf, I don't have a real disagreement with your belief that there must be a supernatural intelligence or being, or something beyond our world. And neither is it problematic to say there is no rational basis for your beliefs, because that is true.
What is a problem (logically) is when you say you came to the logical idea of Gods existence.
Your 'humans are imperfect' argument has a myriad of inconcsistencies that have really been touched on.
But even more problematic is the notion that because God exists, somehow a monotheitstic religion must be the true way of thinking, because only a single entity can be perfect.
You're a Catholic you say?
Well I would challenge the assumption firstly that the Christian God is 'perfect'. In the Bible, God is depcted as failing to predict things, failing to realize the consequences of his actions, being petty, throwing temper tantrums when man is acting up (and flooding stuff), and being really jealous That sounds a whole lot like the behaviour of the Greek Gods if you ask me.
And on a more basic level, the problem with your perfection argument is this. If the world is inherently imperfect, well, God can't be intrinsically linked and all powerful in this world. That would by extension taint God with imperfection. On the other hand, if God is distinct and intangibly linked with the world, well then we can't really come to any conclusions about wht is really like.
Following that thought, most of the Bible and all the Jesus Christ stuff and all the parables are complete rubbish on the truthiness-scale.
Archonix actually dealt with alot of this so I won't really go on as much of it would be repitition. But I hope you see the counter-arguments to specificaly Christian theology.
At Invictus: problems arise when the forces of Religion claim faith and God are supported by logic and Science. Then he battle is over home turf :P