Are you a Satanist?
This is a bit of a loaded question, since there are several different conceptions of what Satanism really is. Most pagans do not worship Satan or practice Satanic rites. Some pagans practice something called Satanism, but it is a far cry from the Hollywood image of Satanism. These people tend to value pleasure as a primary motivation, or to find meaning in images which the repressive Christian churches attacked. For some of these folk, reclaiming the word "Satanist" is an act of resistance against oppression. For more information on Satanism as a religion, please check out alt.satanism.
If what you're really wanting to know is do we sacrifice babies and worship an evil incarnate, the answer's no.