Blue Lithium: Actually, any anti-Christian extreme metal band would do the trick. And while we're on the subject, being a metalhead, I should recommend a few. Lyrically, some of the better ones are:
Immolation
"Can you show me that you really loved us
That you really died to save us from damnation?
I don't think you can, I don't think you will."
Asphyx
"2000 years ago
Someone died
He is known to man as the son of a god
What kind of father lets his son die?
His time will come; an eye for an eye
Look at a history of 2000 years
There's no joy left; there are only tears"
Acheron
"2000 years ago has been enough, it's time to cast out Christian thought"
Gamma Ray (not extreme, but a hell of a band)
"God is an illusion and there ain't no paradise
and there is no underworld below
Out there is no Heaven and there ain't no Antichrist
Welcome to the real World
and the show!"
And of course, the originals
MOTORHEAD!
"Don't need no blind belief
Don't need no comic relief
Don't need to see the scars
Don't need Jesus Christ Superstar
Don't need no Sunday Television
Bet your life you don't need religion"