Does Solipsism count?
Get off my lawn you figments of my imagination!
Worship of Coyote as he is represented in Crow mythology. (I want nothing to do with the Navajo Coyote, thank you very much.)
ETA: If I have to choose a whole mythology, though, I’m not quite sure I’d want the rest of the Crow mythos. So, I’d then add my vote to the FSM.
While I’m tempted to say the same, I wonder how that would work, just like I sometimes go :dubious: in certain eclectic circles. I mean, do you think Thor and Diana would get along? Would Sekhmet crash the party and drink all of Dionysus’ wine? Would Brigid slap the hell out of Aphrodite for being a silly git?
I think we need to get a bit more specific, or we’re going to have a Clash of the Titans for sure. 
Who’s asking?
I pick neo-paganisn. “There are many ways to the goal.” So all the other religions can have their way… except that they don’t get to force others to it.
Okay, don’t show It to me. Now put It back in the deck.
Is THAT your god?
Whaddaya mean, stripper deck?
Czarcasm, I’m one of the only posters who adhered to your restrictions and chose a religion. Aren’t I to be commended? or at least to have you shred my choice by laughing at all the horrible things that are going to happen because I didn’t think things through enough?
I’d choose Christianity. (Or in other words, I’d vote for the status quo.)
One of the only posters? What does that mean?
Which flavor?
What it says…you know, a lot of other posters posted about wanting to choose one tenets or picking apart the notion of “reality” or so on.
[nitpick]Tenet. Not tenant. A tenant is someone to whom you rent a room.[/np]
Pantheism.
I…don’t know what you’re talking about? 
On second thought that would make Tom Cruise like the emperor of the universe, so I change my mind. I’ll go with either the Ethiopian Zion Coptic Church or Unitarian Universalism.
Since I’m asking for a single established religion, I’m going to have to disallow any variations of Panthism, neopeganism or the like, if you are trying to get away with letting them all exist equally. Pick a card, any card, but put the rest of the deck back down on the table.
Hinduism
It’s got a lot of cool gods and you get to be reincarnated. Plus it’s diverse enough everyone can be happy.
“One of the few” more approaches your definition.
I still don’t know what “one of the only” means. It says nothing about relative numbers. If nineteen out of twenty said “x,” and so did you, you could say that you were one of the only ones to say “x.”
Without a quantity attached, it has no meaning.
Stickler. 
Fine. Will you allow atheism?
No.
Atheism, what, it’s an “-ism” just like the others, Science dammit!
Okay, fine, if I can’t have Atheism, then I choose Cthulu-ism