Yeah, actually the more I just thought about it, Batman is probably a liberal. I don't know if he'd be part of any political party and would vote and throw fundraisers for candidates he likes, regardless of party, but nationally he's more inclined to agree with Democrats. He believes in social responsibility and that the rich, like himself, have a duty to improve the lives of the poor and unfortunate and that in a society that it is their duty to provide a social safety net for the downtrodden and those who suffer at the bottom of a community--probably from his very New Deal-esque father's values. But, on matters of local politics he can be more conservative. I think he'd probably believe in more robust law enforcement and the right of authority in the pretense of security over the rights of the individual. Probably why he loved Harvey Dent when he was DA.

That said, Frank Miller's Batman is a hardcore far, far, far-right fringe conservative, if not an outright fascist.
Peter Parker just doesn't strike me as someone who pays attention to politics. He's too into his personal life and too "everyman" for that. But given he's from Queens, he's probably a registered Democrat and as a New Yorker would be disgusted by the Republicans' social platforms (anti-gay, anti-hispanic, anti-Muslim anti-youth, anti-minority).
Superman was raised in Kansas with good midwestern values. He's a Republican probably right down to believing marriage should be between one alien and one woman [blackout]

[/blackout].
Daredevil doesn't believe in the death penalty, takes pro bono cases for poor people in his crappy neighborhood and also believes in social justice and responsibility. Bleeding heart liberal.
Iron Man, as I said, is a moderate Republican. He started out as a neoconservative, but given he quits manufacturing weapons, refuses to give his tech to the US government because he does not believe in the theory of M.A.D. and nuclear deterrence, and goes into manufacturing free cheap renewable energy, he would definitely have drifted left and be crucified by Fox News and CNBC for turning his back on America, capitalism, "freedom," etc. However, given that he trusts in his own personal ability over the government and prefers the private sector, he'd still be on the right. But more like the old school moderates they ran out.
And Punisher is a gun-crazed wingnut.
BTW this all goes back to
Watchmen. Alan Moore characterized most superheroes and rightwing nutjobs. Rorschach, most people's favorite character and the story's narrator, is a parody of the ideal "Objectivist" of Ayn Rand. He is also delusional and a misinformed hypocrite who admires "big tough" leaders like Harry Truman who nuked Hiroshima and Nagasaki to end a war, but dies to condemn snobbish and elitist blue blood, bleeding heart liberal Ozymandias who essentially nukes New York to avoid WWIII in that story. So, the idea of the hero or ubermen being different forms of absolute fascists is an interesting idea to explore.