Religion is a good thing and a bad thing. Humans need religion and mythology to help explain to themselves why things are the way they are and to make them comfortable with natural occurances such as death. However, this has been molded by people who like to take advantage of others, this religion has become a joke. Is there a god(s)? I don't know. No one does. Moving on.
I'd say yes and no.
Religion and mythology are there to help form both personal and group identity and to help make reality more participatory in general. Part of that means situating major life events like birth, marriage, death etc. into a storytelling framework, part of that means becoming the tribe's ideology writ large. Sometimes religion is a weapon of the oppressor, as it was with the Romans deifying dead emperors and adding them to the local religions' pantheons. Just as often, though, it is a tool of the oppressed, such as the Jews using Genesis to subvert the religion of the Babylonians who had enslaved them, or Jesus teaching that God is invoked with every ethical action, or Bhodisatva telling the Emperor of China to go fuck himself.
Now, people I know variously assume me to be Christian or atheist. They're both right in a way. I'm atheist towards the capital-T Theistic "God" of Pat Robertson and the Pope. That language game doesn't work, because it asserts absolute truth value on the authority of its own proposition, which is contradictory in and of itself, but the double-whammy is that omnipotence, omniscience and omnipresence are words that do not refer to anything, but only serve to mask an agenda of dominance. An omnipotent, omniscient or omnipresent being can't possibly exist (see Russell, Godel, and Heisenberg). However, I am also Christian as the Gnostics were Christian, as Therese of Avila was Christian, as William Blake was Christian, adhering to Jesus's original message that through inner contemplation and outward kindness we come to the realization that reality is itself Divine (which, if you think about it, is also the message of Buddha, Lao Tzu, and Mohammed).
In short, there is no "God," but there is G-d, and we are Him.
Smaller gods, of course, do exist. The question is, what is their ontological status? Do they exist as objective beings, like foxes? My atheist response would be no. But do they exist as emergent beings? My Christian mystic response would be yes. Patterns of behavior self-organize and coordinate across populations, to the point where these transpersonal memetic bits of culture acquire something like semi-sentience in that they desire to persist in their own being; if the war god acquires a foothold in your culture, he demands blood. When the fertility goddess takes center stage, she wants you to visit the temple prostitutes or your crops won't grow. We are symbiotic with them, and in sense, we are them.
This is why chaos magick is so fun. See, it's inarguable in my mind that magic exists, whether it's the Tobriand Islanders performing a ritual to the Sea Goddess to protect their fishing ships or the baseball player wearing his lucky jockstrap, it's all magic, and it exists in every culture. To ask whether magic is "true" makes as much sense as asking if a wrench is "true;" the only important question is, "Does it work?" So when I perform rituals designed to invoke or converse with gods I don't have to believe they exist, but I have to treat Kali nicely, or else she won't empower me like I want her to.
Because Kali may not have objective existence, but you know what? Neither do I. This whole identity I've constructed called "Jason" is a fiction. We are all stories we make up as we go along, and we all invest in our stories an unproven amount of belief. So self-righteous Christians, atheists, and what-have-you that insist upon the absolute primacy of their own "truth" better take a good long, hard look in the mirror. What you see is only a body. Your likes, dislikes, experiences (memory is just past events reconstructed to serve current objectives), your whole personality is as unprovable as any god. It has no existence, until you give it existence.
To which the chaos magician responds "Why not make it interesting?"
(And to the fussbudgets that scoff "There's no such thing as a Christian atheist! That's like a married bachelor!", I introduce to you the world of Don Cupitt, Mark C. Taylor, and John Shelby Spong.
Radical Theology for teh win!)