It's really fun to talk to friends about things you like. I get really excited when I talk to my friends about Pride and Prejudice, or Batman, or Harry Potter. However, not all of my friends have the same opinion about these things as I do. Some think Matthew Macfayden made a good Mr. Darcy (I really really REALLY don't). Some people think that Ironman is better than Batman (he isn't). Some don't even LIKE Harry Potter (I just try to ignore that). Usually, my friends and I argue about stuff like whether Snape is a good guy or not, or who would win in a fight between Aragorn or the Master Chief.
Philippians 4:8 gives us instructions on how to think: "Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things." Ephesians 5 tells us how to speak: "Let there be no filthiness nor foolish talk nor crude joking, which are out of place, but instead let there be thanksgiving." Now, does that necessarily have anything to do with comic books, movies, or tv shows? Well, yes and no. It doesn't say we're not allowed to enjoy these things, but it does limit them to things that fit these qualifications. Also, focusing on these things to the point where we argue with our christian brothers and sisters about them, is wrong. I am embarrassed to say that I have gotten mad at people because they've said one tv show I didn't like was better than a show I did like. Don't let Satan use these things to make you mad and fight, or even just "pretend" argue, because it will just cause problems in the long run.