For me, it's probably going to be DC.
I don't really know why, but I actually do love Marvel and DC both, but if I really did had to pick a favorite, DC will ALWAYS win.
The reason for that is because, as some of you guys said before, the Marvel movies are great (though I don't like the romance parts... yuck)
But DC comics is a classic, because of Batman and Superman.
But also because of Teen Titans, and other various superheroes. And to be completely honest, I know more about DC characters more than I do Marvel, though I know some stuff about Marvel as well.
For the most part, they're both pretty awesome, but picking between them isn't really a indecisive thing for me XD