Most of my values are similar to those expressed by Christ in the Bible, too--but not because Christ said them, more because they make obvious sense. I don't oppose Christ's values; I think he was a great philosopher--I just don't think he was more than a biologically ordinary man, and he's going to stay dead forever.
I think you've made a false distinction between "agnostic" and "theist"; in fact, I would argue that you're both. I don't see any problem with agnostic theism of some sort, and neither do most atheists. The only problem we have is with insistence on particular moral values and dogmatic practices, with the idea of God as an external, independently existent person who enforces those values on the world. There's a reason that people tend to assume this is what you're talking about when you openly declare belief in God--your arbitrary conception of God is not what the term means to most people, and so of course they'll misunderstand when you use such misleading terminology for your belief system.
Don't take this the wrong way, but whatever it is you found--worthwhile and a positive force in your life though it may be--simply is not God by any modern religious standard. Why can't you call it something else? It has little to nothing in common with what the vast majority of people today believe about God, and continuing to use the same term for something completely different only causes confusion and massive internet flame wars.
For a counterexample, let's pretend for a moment that I'm a Nazi. No, I don't support white supremacy or Hitler's ideals or have anything against Jews. No no, that's not the kind of Nazi I am! Regardless of what 99% of people who identify as Nazis seem to think, I have my own definition of Nazi which involves total racial equality, nonviolence and pure open-mindedness. Not only that, I'm going to get very upset if you say anything bad about Nazis or claim to oppose Nazism--you're just not respecting my personal definition of what a Nazi is! Shame on you!
See how quickly this gets ridiculous? If there's no standard definition of Nazi, then anyone can classify any belief system as Nazism, and the same goes for theism. If I think God is my big toe but don't believe in one scrap of actual religious tradition or scripture, news flash: I don't actually believe in God, no matter how real my big toe is!
I'm basing this on what *most* people who believe in God believe about him, not on some arbitrary personal/factual definition. "What is God?" is dependent upon whatever the most popular conceptions of God say about him at this particular point in history, and nothing more or less. If most supporters of God agreed with your conception of him, I'd probably define myself as a theist, because I see validity in the experiences you've described. But the fact is, no matter how uncomfortable it may be for you to accept it, you don't actually believe in God, at least not with a capital G, and if you need evidence of what God really is, just look at popular religion--what other standard could we possibly use to come to a common definition of God?
I know, I know--we don't need a common definition, right? Because God can be anything anyone wants it to be, right? Well, no--if we accept this premise then all belief is theism and all belief is atheism, and the terms become entirely meaningless.
Atheists don't claim that science has solved 100% of the universe's phenomena. Not even close! We guess that most of it can some day be explained by science, but we also understand that some of it can't. This is where there is room for spiritual belief--to explain the unexplainable. Fair enough, but I think that those of you who use such incredibly vague, loose definitions of "God" (whittling them down further and further every time something irrational comes up) are simply in denial about being atheists and don't want to alienate others who profess belief in God.
Atheism doesn't require total lack of spirituality or some silly dogmatic faith that science can explain every question the human mind can ponder.