Considering the varieties of religious expression that have existed and still exist, I consider this question more fairly worded than on the previous forum. "Do you believe in God" has an inherent bias in it towards (male) monotheism. If you don't believe me, ask yourself if the question "Do you believe in Goddess" would evoke the same reaction and if not, why not?
Personally, I don't believe there is any neutral way of asking this question without revealing biases. "God/Goddess" still implies monotheism. I suppose one could ask, "Do you believe in Gods/Goddesses (plural)?" but this question would probably not make sense to a monotheist. Likewise "Do you believe in God" does not make sense to a polytheist who would have to ask, which one?
For the record, if anyone doesn't know by now, I am an agnostic (meaning I don't know) atheist (meaning that I don't believe there is anything supernatural outside the universe as we know it).
The way you could fix this would be to ask, "Do you believe in any sort of God(s) or Goddess(es)?" It's still more confusing to the monotheistic mind, but that mind can still understand this sentence. Anyone who isn't monotheistic would have zero trouble, as would atheistic or agnostic individuals.
I used to be an agnostic too, actually... and even now I am still questioning basically everything Christian. This does have to include God on some level, because my idea of God comes from the Christian faith, generally speaking. I question whether Jesus was actually any sort of prophet, let alone a savior; I question how much of the Bible (the entire Bible) is actually true and how much may have been made up; I certainly don't believe in things like Jesus being born without sex being involved, although IF God did exist in the form he is presented in via the Bible, he COULD make that happen. But that leads to the question about whether God exists as the Bible would paint him.
I've just recently purchased the New International Version of the Bible, as it's the most well-researched and accurate translation to date, and I find myself troubled by a lot of things I read in it. This idea of an angry, jealous, vengeful God, for example. I do not believe God is like that, and if I did, I would not worship such a god. Period. Anger and vengefulness, especially the latter, are two things I detest, and they also utterly conflict with my first ever feeling of God coming to me: pure and total joy. God came to me basically as unadulterated joy that definitely did NOT come from me, because I was utterly joyless before that moment. But suddenly I was filled with it; and every time I would pray to God in the following days and weeks, the same feeling would come over me and fill me and just radiate through me very powerfully. THAT's what I believe God is. But even Jesus talks in the New Testament about how God gets angry at things, and even Jesus uses his (so-called) Godly "powers" to, for example, destroy a fig tree because he went to it when hungry and it had no figs. Like, what kind of Son of God would do that sort of thing? Is this a Son of God I would WANT to worship? (And couldn't he have just used the power to make the fig tree bloom?) I know this example sounds small and possibly silly, but there are many more similar to it... I just haven't read enough of the Bible yet to be able to quote examples. I haven't even gotten through Matthew, and I've started my studies with the New Testament, so.
Basically... if I ever DO again become a full, true Christian, it will be because I studied the Bible thoroughly, and made a critical examination of it, and also of myself. I still lean very heavily towards believing in God, to the point that I probably do at least believe in a force of that joy, or a force of good, in the world. But I've never been sure if that force is somehow equal to whatever created the universe (as in, the same God did or is both things), and IF God is in any way vengeful or angry -- and if so, why would he have those emotions in the first place? I know for a fact that I do not believe in hell or Satan (as an entity; there are definitely forces of darkness in the world, too), and I have doubts about heaven, although at this point I'm believing in spirits, thanks to Long Island Medium. If you can't tell, everything is very confused for me faith AND religious-wise, so it's no wonder I'm turning to texts to study to try and figure it out. When in doubt, research research research till your brain can't take anymore, then repeat the process as many times as you need to to try and figure out the answers to your questions. That's just what I do.