Nintendo has released a few more details on both the starter pokemon and legendary pokemon found in October's Pokemon X Version and Pokemon Y Version.
For those who hadn't already figured it out, the three starter pokemon are water, grass and fire types. Fennekin the fire type is strong against Chespin the grass type, which is in turn strong against Froakie the water type, which in turn is strong against Fennekin the fire type. I'm glad that's clear.
In addition, Nintendo's released some vital statistics for legendaries Xerneus and Yveltal:
Xerneus, 3.0 m (9'10"), 215.0 Kg (474 lbs.)
Yveltal, 5.8 m (19'00"), 203.0 Kg (447.5 lbs.)
Source: Press release