Varanfan9 said:
Wait, define fictional gods? I'm honestly not trying to be a smart ass or offensive towards religious people or anything by saying this, but you really can't say "Greek Gods are fictional but Christian ones aren't."
I'm sorry, but that's ridiculous. It implies that we know deities that are currently recognized are real, and we know that older ones are not - Which is not true, fact.
Now, maybe the OP actually just meant deities mentioned in fiction that doesn't ever aspire to be fact, and a lot of people who replied just took it to include ancient religions, I dunno. Hence I quoted the OP in the hopes I'd get clarification.
OT: Assuming it is the latter, I'd have to go with The Force. It's not like many other ideas of Gods which work kinda like a monarch, where one guy has control all the time. Just a vibrant, everpresent energy.