Current:

George Soros, the old multi-billionaire. Actually paid Georgia to invade Ossetia, thousands of civilians killed - how evil is that? Paid people to riot in the USA, at Ferguson and elsewhere. Much of the evil in the world today is financed by Soros.

All-time:

Karl Marx. At least 100 million innocents murdered in China, Cambodia, USSR, etc in the name of Marxism. And much of the evil in the world today is the result of Cultural Marxism.