I am pumped about this.
Obviously there's the fire/water/grass trio going on, but some folks have noticed a reverse effectiveness possibility.
Fennekin used some sort of psychic move that resembled psywave or confusion. So, Fire/Psychic.
Chespin used a dark-tinted claw attack that I would guess as Night Slash or Shadow Claw. Grass/Dark. (Though it sure isn't a Shiftry.)
Froakie is... well, it has gloves and I think that was Close Combat it used. Maybe it'll look more like a fighter later. Water/Fighting.
Psychic > Fighting > Dark > Psychic as well as Fire < Water < Grass < Fire. Neat, eh?
I'm just glad that fox thing is unlikely to turn into another fire/fighting type. Though I'd call it 50/50 that Gamefreak goes a-trollin' and gives it a popout fist or something in its third evolution. I'll probably be going with Froakie to keep parity. I've done
Charizard,
Meganium,
Swampert,
Infernape,
Serperior, so it feels right to choose
Froakie.
X and Y look pretty neat, though X seems like a grass legendary that would overshadow the previous (Celebi, Virizion, etc), as well as having that Kyogre>Groudon problem of being slaughtered by the other cover legendary, assuming that Y is flying. This could possibly be counteracted by secondary types, but I'm at a loss as to what they could be. Perhaps Flying/Dark or Psychic for Y, but X seems like... a rainbow-horned Great Forest Spirit.
vs.
Either way, the giant devil-bird is pretty rad, so I'll be getting that version, pending further information.