responding in part to Ruthven's post...
no, christians (or lutherans, at least; i don't know enough about other denominations to generalize fairly) don't believe that doing "good works" will get you to heaven, because we are sinful beings and no work we do could ever be good enough for God. rather, we believe that God loves us, and grants us eternal life if we love him in return and accept his gift (for God so loved the word that he gave is only son, that whoever believes in him shall not perish but have eternal life)
the "unrealistic standards" aren't there because we're expected to be able to meet them; as sinful beings, we can never meet God's expectations, and the law is there to show us that we can never be good enough to "earn" eternal life on our own, but through God's mercy and love, we are granted eternal life through Christ's sacrifice
so no, a satanist could not do "good" enough to get into heaven; no amount of good works can do that. the only way is to love and accept Christ.*
*[Disclaimer: this post represents my beliefs, and what I have been taught that the lutheran church beleives as a whole. not everyone believes what I do, and I'm not intending to force this onto anyone. just offering my side of the discussion)
Moo.