Leo Trotsky, Hugo Chavez, Che Guevarra, Anakin Skywalker...
I have a tough time calling at least the first three "evil". This just seems like 'socialism/communism is bad no matter what' stuff that's left over from the Cold War (and the fact that Mao and Stalin pretty much totally redefined what these political theories were supposed to to fit what they wanted and turned it as far away from Marx, Lenin, and Trotsky's not-so-authoritarian ideas as they could), when good people have and can support it. I'm not claiming sainthood for anyone, but certainly none are evil.
Trotsky and Stalin were extremely bitter rivals, Trotsky hated Stalin's ideas for the Soviet Union, having far more in common with Lenin. Lenin wanted Trotsky to lead Russia after his death, and was scared that Stalin would turn his it into something awful (he did). Lenin and Trotsky were also some of the largest proponents of the time of ending anti-semitism and, thanks to a similar mindset, was among the first nations in the entire world to legalize homosexuality. Their revolution was because the people were legitimately oppressed by the capitalist Czars, and both Lenin and Trotsky held onto that sense of creating a more balanced society. Their intentions, and as far as I can see, their actions, were good.
Chavez I'm less defensive of, but think he's way too villainized by the US. admittedly hates the US, but that could have something to do with the fact that there is strong evidence the Bush administration attempted to stage a coup against him, and we're constantly calling him a shithead. He doesn't round people up or kill journalists, and he saved Venezuela's economy from the toilet to make it one of South America's best (though the economic crash is taking its toll fairly hard now). He's also done a lot for women's rights in Venezuela (his brother is a women's rights activist). He's been a long time friend to Haiti, and is sending significant aid to them after the earthquake. He is arrogant and a little to reluctant to give up office, however, and the allegations of being a bit of a propaganda-monger I don't know enough about to confirm or deny.
Che I also believe his revolution was driven from a point of genuine goodwill. As a medical student, he travelled through Latin America and helped a lot of poor countries, and in fact the extreme poverty he saw made him a socialist. It was a cause he was killed for, of course, by CIA aided Bolivian forces. He also fought against the CIA/United Fruit backed revolution in Guatemala (basically the US overthrowing a democratic, non-socialist leader for a military junta over United Fruits profit margin). Chavez lost that one, and the right-wing military junta the US's efforts put in place was unstable and authoritarian. It took Guatemala almost 50 years to regain a stable government and stop constant crime and revolution. He participated famously in the Cuban revolution. Against an incredibly corrupt government (run by a man commonly considered a dictator himself on account of severe intimidation and allegations of other voter fraud in elections and whom had had at least two unsuccessful coups) which dealt pretty much openly with organized crime and who violated human rights. Over 75% of the people became so disillusioned with him, his refusal to acknowledge their needs and rights, and his electoral fraud that they boycotted voting 1958, and the US even stopped supporting his regime. Cubans were miserable. Guevarro did some stuff that was a bit dirty and questionable, he fought for people in a big way. Some would argue the best way.
These aren't Stalin, Hitler, Pol Pot, Kim Jong Il, Ted Bundy or the Joker. Some might argue they aren't even as bad as the CEO of Bank of America. I'm not a socialist myself, but I don't like the blind "socialist = pure evil" assertion that seems to be left over from a war twenty years over. We installed and supported some pretty terrible right-wing dictators in those days, and I thoroughly believe that sometimes we even supported the worse of two evils. Especially in Latin America.
PS, Sol_, don't forget arguably the most terrible villain Fiennes ever played: Amon Goth in Schindler's List.