Really now? I wouldn't consider myself an agnostic in the least, although I can accept if I am wrong, but I will need some evidence to make that conclusion. I am an atheist, and I am sure gods don't exist because we lack evidence for such beings and it maybe possible, but it is hardly plausible. Not only that, but god(s) and religion changes from culture to culture and from era to era, and this just shows that is more of a construct and function of the society within which that god(s) or relgion(s) is/are found in the era within which it is found.
I am not saying that if evidence were found that god(s) existed that I would not consider that evidence. If it were strong, verifiable, quantifiable evidence, I would change my opinion, but alas I don't see that evidence anywhere, and in thousands of years of looking, it hasn't been found as of yet. I will not believe until such a time as evidence is produced.
At this juncture, religion is mutable, and that is a big point against it since it is the very religion that propounds that god(s) exist. No religion has survived intact (in the same form with the same beliefs that it began with) after a few years much less hundreds or thousands of years. We can see some fine examples of this in some of the most well documented religions such as christian mythology, ancient Egypt mythology, Greek mythology, ect. These are religions that changed and adapted over time to changing societies to the point where their gods even have changed positions on major issues overtime following the patterns of the society within that religion is lodged.
So is it plausible to believe? No. Is it rational to believe that we don't know? I don't believe so since there is absolutely no evidence nor even any consistency within the belief systems themselves that would support the existence of a supreme being. Not only that but I think I don't know is a much more plausible and possible answer.