Aleister Crowley. "Do what thou wilt shalt be the whole of the law." Really nice when you actually take the time to think about it. Not that he wasn't an insane pr*ck. He just was the sort of insane pr*ck who happened to do some awesome stuff. Like make a Tarot deck and creating the "The Universe" arcana.
Actually, that quote from Crowley (which for whatever reason often gets associated with Lavey) is a big part of the reason why people of those particular persuasions are often looked at as egotistical or selfish.
The whole do what thou will shall be the whole of the law thing often gets misconstrued as "do whatever you want with no regard for anyone else"
Sadly this misunderstanding mainly comes from the fact that the accompanying passage always seems to get lopped off.
"Do what thou will shall be the whole of the law. Love is the law, love under will"
Crowley was an odd dude but he had some interesting writing from a philosophical view point.
Oddly enough, I often find the people who find the idea of "Satanism" to be so revolting are those who know nothing about it and often associate it with other things that have nothing to do with Satanism at all.
The inverted cross is probably one of the best examples. Zomg unholy symbol of Satan! Except for the fact that it was the symbol of St. Peter in Christianity because he supposedly requested to be crucified upside down because he didn't feel worthy of going out in the same manner as Christ. St. Peter was heavily tied with the Roman Catholic church as well, which explains why that big fancy throne the Pope sits in has a bunch of giant upside down crosses plastered all over it.
But you know, they all must just be filthy heathens.