I have to admit to being confused by the thread, just a bit. I read the title and thought, oh hey, discussion of spirituality vs. rigidly enforced rules and rituals; then found it was really more like "God = Christian?" which is a topic rather more narrow in scope. What's the difference, you might ask? Well, I was going to open with something leading toward Taoism or Buddhism where, no, following a religion does not equal belief in God, or even god, necessarily, and goes in an entirely different direction...but oh well!
I'd say Meikle's going in the right direction there. It's a little odd to look at a conversation that is, essentially, "Do you believe in Christ?" "Yes, but I'm not a Christian." It's just...I mean...that is literally the defining trait of Christianity. It's in the name. I could argue that, from at least a surface reading, even if you envision Jesus being something rather different from any existing branch of Christianity, you're still under the umbrella of "Christian" by virtue of having Jesus as your focal point for what a perfect human being can be and your example for what we should all try to live up to in life. Some other, wholly new variety of Christianity, but definitively linked none the less. If, on the other hand, you believed all humans were divine and Jesus was just another guy, rather than this unique purveyor of miracles and so forth as "an example of what we all could be," that'd be another story. From what you've said so far, though...I think I'd need a more detailed explanation of your beliefs before that conversation could go any farther, really. We're just working with extremely basic concepts from both sides - yours and Christianity's - and on that level they don't seem extremely different, which would probably lead me to ask, "How are you not a Christian," myself. Not in an accusatory way, more in a, "Seriously, explain to me in what respect you aren't," way.
Note that that's not saying "you must be Christian to believe in Christ," it's pointing out that believing in Christ (spec. with regard to his being part of/exemplifying a higher power, not just that he existed - I'm pretty sure that Islam, at the least, also makes reference to Jesus, but not with the reverence Christianity does) is what defines being Christian. Claiming to believe in Christ but not being a Christian is rather like claiming to be a vegetarian around a mouthful of steak. It's not that you can't DO it, it just...sounds strange. And contradictory.