Go go go for those falltones, they're so pretty and they fade so fast. You're on to something about coloring those lines, but i didn't want to ' break' too much with the lines on the girl, for sake of consistency. You're correct that it does look dirty, i'm on an CRT so that might be the cause. Not coloring the lines or rather painting them in was a less successful decision, looking back, they just don't settle there.
I love playing with textures, though i admit it's an easy way out. They often influence my decisions about color or rendering, so i should tone that down a bit. But its so much fun!
Here's one without textures, for the Blue thread in the Superheroes section