While I'm not a socialist (I'm an independent), I would have to go with Eugene Debs. From all accounts, he had a real compassion for Americans and the common man and woman (and not just mere political motivations). Similarly, while I don't agree with all of his policies, I'd have Teddy Roosevelt coming in second with the Bull Moose. Roosevelt was just a "frickin'" awesome man, barring the racism and stuff. lol.