I don't really object to a darker setting or narrative. I rather like works that have that same conflicting morality/mortality that Skallagrim mentioned, though I appreciate when there is some disparity in that aspect. The whole "too much of a good thing" argument.

To mention a few examples of inspirational material of a darker kind I suppose Berserk (manga), Dark Souls (I love the lore involved with the games, though I favor the first one), the Shin Megami Tensei series (and a few of its older spin-offs), and (though I suppose it not everyone would consider it to fit that description) the Megaman Zero series on GBA. Unfortunately for me, I don't know of many "darker" superhero series besides those centered around Batman, so I can't say I can give much direct reference material.

Also, in case anyone missed it, I added onto my previous post in this thread to explain a few other things that inspire me to write.