people definitely get the wrong idea about things like this... there are, from what I have been able to find out in my studies, THREE main types of "Satanists":
1) atheistic or symbolic - they are from the Anton LaVey camp. They don't believe in anything beyond this existence, and the word 'Satan' is just a boogie-man invented by the Christian Church to keep people in line. You live, you die, and that's it.
Personally, I've found this a little hypocritical - if 'Satan' doesn't exist, then what are they doing during ritual, playing dress-up? Lying to themselves?
2) reverse Christians - they believe the Bible is correct, they just side with 'the bad guy'.
My only reply is "WTF?!" LOL
3) Pagan or Theistic Satanists - they believe that "Satan" was a pre-existing Pagan deity that has been maligned by the oppressive control structure of the Church. The gods of one society become the demons of their conquerors.
I think this makes the most sense - it's absolutely documented and provable that the so-called "demon" Astaroth was in fact derived from the Pagan goddess Astarte or Ishtar. If you look at the traditional depiction of the god Pan, it's not hard to see where they got their 'devil'.
Just a little clarification... 2,000 years of propaganda is hard to combat, eh?
What am I?
Abit of this... abit of that.