The guy who said Punisher might be on to something, as I prefer more grounded super heroes. Though, Punisher isn't really "super", is he? In any case, I'd prefer to see a take on Punisher over another Spiderman or any other child-friendly superhero.
The only other character I'd be really interested in seeing, if done right, would be Spawn. A grounded/realistic and mature take on Spawn's story would be quite interesting and perhaps would make for a far more engaging story than most of these overdone Superheroes in pop culture.
Flash? Boring. Superman? Boring. Wolverine? Boring. Batman? Boring. Hulk? Boring. Almost all of the common names we've already seen done to death in movies and animation; I have no interest in seeing them!
Give me a Spawn story with deep, dark character-focused story, horror elements with great pacing, writing, gunplay and excellent super power implementation. The Spawn character and Spawn Universe would make for a far more interesting story and setting than most other superhero stories, simply because his story and world is so dark and grown-up. I'm not interested in the kiddie stuff, sorry.