Not nearly so sure yet which starter I'll choose. I'm leaning heavily towards Litten because it's a kitten and has a really cute cry-- the fact that it looks like it might evolve into fire/dark has something to do with it too. That said, I do traditionally go for the water-types and all the hate I've already seen for Popplio makes a big part of me want to choose it out of spite. Plus, the new region is based on Hawaii and so a water type seems appropriate. Granted, if this region ends up being as heavy on water-types as one might expect from the setting, it would make good strategic sense to go for the grass-type starter. It doesn't hurt at all that Rowlet is an adorable little owl ball with a bowtie. Not only do I love owls-- with or without bowties, though the bowtie certainly gives it that extra something-- but it would also be thematically appropriate to Moon. And it is the only one with a dual typing, which makes it stand out.
Honestly, for all that I'm agonizing over this already, it may very well be the evolutionary lines that convince me. I was Team Froakie all the way back when XY was the new thing until we found out Chespin's final stage would be grass/dark. It didn't decide me immediately, but it was what the final answer came to rest upon.
And how about you guys? Excited? Underwhelmed? Do you know which game you'll be playing with which starter?