I like both Marvel and DC, but my interest isn't about the Marvel or DC world. It's simply that I like some characters more than others.
MARVEL
My favorite Marvel hero is Iron Man. This was true LONG before the movies. I first got interested during the "Armor Wars" in the mid-1980s. Both my brother and I have a soft spot for the
Silver Centurion armor used back then. Stark had the whole "Tom Selleck Magnum PI" look going which is hilarious looking back.
What helped the IM movies a LOT was the costume itself. IM's armor is theoretically possible and therefore, doesn't look stupid. Armor looks far more realistic than wearing spandex.
The only hero who wears spandex (and can make it work) is Spider-Man. He's supposed to be agile and flexible so wearing a light costume makes sense. His costume didn't look too stupid for spandex, either.
I've never been interested in Thor. In fact, the majority of the Avengers never did a whole lot for me. I feel differently with Marvel's "Ultimate" line, in which the Avengers are really interesting. I particularly like the fact that Captain America acts like a person, instead of a walking WWII recruitment poster.
DC
As for DC, my favorite is Batman. Once again, I liked the character a lot before the recent movies (including Tim Burton's Batman). My opinion of the character changed a lot when I read Frank Miller's The Dark Knight Returns. Miller's conception of Batman was radically different from the way Batman had been portrayed before (much of which owes its blame to the 1960s Batman TV show).
Miller's Batman was psychotic, brutal, ruthless and enjoyed inflicting pain on criminals. He also considered Superman well-intentioned, but extremely annoying, saw Wonder Woman as an uber-feminist man-hating bitch and thought the Green Lantern was a drooling moron.
Some people might say, "That's horrible! Batman isn't like that!" Really? This is the same man who dresses up as a bat (among other things) in order to make criminals shit their pants. Let's face it, the guy probably isn't the most well-adjusted person around.
Superman is okay too, but I think DC has been screwing him up again. In the 1980s, after DC had its Crisis on Infinite Earths reboot, I thought Superman was cool. They had reduced his power levels (he was still one of the most powerful guys in DC, but he couldn't go around juggling planets anymore), changed the way his invulnerability worked and made him a little less boyscout-like. I think DC is now reverting back to the old Pre-Crisis days, unfortunately.
I liked Kyle Rayner as Green Lantern, not Hal Jordan. Jordan has the personality of a rock, whereas Rayner was interesting, especially when he was new to being a superhero (something that wasn't his choice, either). It looks like the new GL movie will have Hal Jordan in it and end up pretty piss poor too.