Knightfall
World of Kulan DM
Dark Matter would be an okay 4e Modern setting with some options for psionics-based FX. Agents of Psi would fit into Dark Matter without too much difficulty.I know what I don't want - magic! Or at least magic that doesn't make sense. That rules out Urban Arcana and Shadow Chasers right away. Dark Matter is a far more acceptable setting, and you can even see it on TV (it's called X-Files, Fringe, or any sci-fi TV series that doesn't suffer from Sunnydale Syndrome). I wonder... can you fit Agents of Psi into Dark Matter?
Hmm, it sounds like you'd be more interested in a 4e modern setting based on the V for Victory d20 mini-game (Dungeon 97) or maybe the Pulp Heroes d20 mini-game (Dungeon 90).I'm personally a big fan of vigilante, true crime (either side of the fence) or military. Usually said settings have no FX or very minor advanced tech. (Considering how much I hate having cell phones in a campaign, I'd probably veto any advanced tech I saw, but I suspect marketing would require that be included in the setting.) My favorite so far was d20 Colombia, which gave a place to play, plots to breaks up, and NPC descriptions with undefined resources. (You had to make your own stat blocks though, which can be real fun.)
The Bughunters system, Amazing Engine, was pretty unique. I wish it could have had more of a chance to succeed.Sci-fi is a lot harder to do than modern, which is in turn harder to do than fantasy. Sci-fi tech invariably reacts badly with rules. More rules = bad, more tech = bad, high tech and loads o' rules = doubleplusbad. I've only seen the rules-light FATE and Bughunter systems work well with sci-fi. Alternity, GURPS Traveler and Warhammer 40K did passably well, Dark Heresy was overpowered and d20 Future was just terrible, and that was before you got into the settings (some of which were redeemable, if only by controlling tech). Even d20 Star Wars had tech problems, but the focus on cool class abilities and the Force meant the DM simply had other things to think about.