So far (in the first episode), we've met:
* Mohinder - geneticist (no obvious powers, but may know best what's going on)
* Peter - nurse (empath)
* Nathan - politician (flight)
* Hiro - office drudge (temporal manipulation)
* Niki - internet sex worker (alternate personality: brawler)
* Claire - high school student (regeneration)
* Isaac - painter (precognition)
* Ando - no obvious powers, fan of Niki's, Hiro's coworker (no obvious powers)
* Lyle - Claire's brother (no obvious powers)
* Simone - Isaac's girlfriend, Peter's employer (no obvious powers)
* Claire's stepmother - slightly vacuous dog breeder (no obvious powers, but may know some of what is going on)
* Claire's stepfather - villain (global resources/connections, probably knows most of what is going on)
* Micah - Niki's son (genius intelligence)