Christianity is too fragmented and torn. It's sects vary so much in their beliefs, it's hard to find a common belief besides God and Jesus.
Satanism is filled with either people who never outgrew their "angst teen" phase, or Christians that realized that God was a dick for making Satan knowing what he would do, and then punishing him anyway.
Without Christianity neither atheism or satanism would exist. I'll go for the main not the supporting characters. They are trying to upstage a thing they say doesn't exist. In that case atheism and satanism is just a lot of ado about nothing. Sad. They owe their existence and occupation to what they are trying to prove isn't even there. very sad.
At least Christianity is widely considered at worst a self contained myth that doesn't rely on anything else but it's own folly. And they have the best selling book in the world. Not too shabby I say. Along with an unparalleled history and effect on the whole world, the most adherents to the seemingly wackiest things ever, the biggest holiday celebration, the most sects by thousands, the calendar thingy, the most miracle kinda stuff and especially the tiny possibility of God's existence....I'd have to say there really isn't a contest here.
Whether you believe it or not, Christianity is awesome any way you look at it. That I believe it to be bang on makes it even more awesome. I bet it's here to stay, and it's tag-along as well.
You seem to be an open person. My interest lately has actually been in parody religions. I think you will greatly enjoy the ones I post below. Google them and have a good laugh.
Church of the Invisible Pink Unicorn
Church of the Flying Spaghetti Monster
Church of Google
Westboro baptist Church (this ones real, but no less funny, and scary)
Christianity, Atheism, or Satanism?
