I use actual facts and statements from the comics, movies, tv shows and anime, (depending on the character) to determined the outcome of any battle. I'm not biased, I find it more fun to know who actually wins a fight, then just voting for your own favorite character. A few of the many important things to consider when answering a battle is heritage, experience, strengths and weaknesses.
My all time favorite character is Hanna-Barbera's Scooby-doo, he inspired me at a young age to be the artist and writer I am today. My favorite superhero is easily Captain America, but my favorite quote is stated by Superman.
"There is a hero in all of us, we just need the courage to put on the cape"