The main character? With the blue hair in a ponytail? That's Tyson.
And the hyper yellow haired one is Max.
Max can get pretty annoying, but Tyson's alright if he keeps his mouth shut. Daichi makes me wnat to rip his head off...
Rei (the chinese one with a ponytail down to his knees) and Kai are good, becuase they're quiet, and don't bounce around on sugar overloads.