Okay, ZK, I have a few different concepts I'm willing to throw in the ring. Let me know your thoughts on these, and I'll pick one to stat up.
A more iron-age-ish coming of age type hero. He's on the tail end of high school, and gets powers through some accident of Science!* He has a mild schism in his personality; his super-hero persona is actually a voice in his head, and was active for months (while his normal ID was supposed to be asleep) before he became aware he was going out at night. This is probably the outright darkest character concept I'm likely to toss out, as The Ghost is a much more vigilante, vengeful type of hero. He's most likely to go after gangsters, thugs, and madmen, more of a street level Batman/Punisher/Daredevil vibe. He's a scary-ass boogeyman out to get some payback for the normal people who get pushed around.
Powers: Enhanced speed and agility, Insubstantiality, Regeneration. Also carries some normal weapons and low-level devices, such as guns, night-vision goggles, and maybe the occasional portable power tool or chainsaw.
A minor brick. This character is a lapsed Catholic who started to develop paranormal powers while growing up in a nun-run orphanage. How in his mid-to-late twenties, he lives as a practical recluse running a junkyard on the city outskirts. He has the unfortunate ability to see all the guilt and sins on a persons soul in their aura, and it's turned him into something of a misanthrope. He's a good guy, genuinely charitable, kind, and tries to be forgiving. But he can't be around much of anyone without being assaulted by all their petty wrongs, let alone if they have any real skeletons in their closet. He can also transform into a big, powerful, mostly-invulnerable form with a demonic/gargoyleish appearance, sometimes by accident if he gets too angry. He's sort of a brick light - he lacks the superstrength of the standard brick, but has some tracking ability to make up for it. The major drawback is that he could potentially ruin a lot of mysteries - he knows what someone is guilty of when he sees them, at least in a hazy and abstract fashion. If this isn't a mystery-oriented game, then that's fine.
Powers: Strength, Invulnerability, Tracking, Sin-Sight, probably a small amount of flight.
Imagine if Inspector Gadget wasn't a total joke. This character was part of an experimental superteam developed to clean up Detroit when it started to fall apart. They were all manufactured, custom-made. Even the mystic was empowered with an artifact that had been stored and studied in a lab somewhere. The theory was that they'd be more professional and directable if they all had their powers originally granted by the city authorities, and if they all initially trained together after getting them, so they didn't bring any bad habits to the team. The theory was that this would make a more stable and effective super-team.
Well, look at Detroit and see how well it worked out.
This character had pretty much every part of his body replaced with cybernetic augmentation. He looks human, but he's got more gadgets in him than the new female model in Terminator 3. After the team disbanded in a wave of scandal (infidelity, alcoholism, and corruption high on the list), he took on a newly constructed ID and a few night courses in business management, and tried to settle down as a normal person with a mortgage, a car, and a dog. They didn't have the budget to take any of the stuff out of him, so he just figured he'd stop using it, and that'd be fine. Well, his job transferred him to Paragon City, and...it's hard to just stand by when people get hurt. Real hard. He hates the fact that he's going to go back into the life, but he's probably not going to be able to pretend he's not what he is much longer.
Powers: A lot. I'll probably take some fairly standard attack/defense/mobility powers and make up the difference with a mechanical-themed Shapeshift, to represent the incredible amount of technology packed under his skin.
*Science! is not anything like real science. Real science involves labs and beakers and peer-reviewed articles. Science! has all that, plus tesla coils, killer robots, and gamma ray mutations.