I WANTED to pick Finnekin, but Delphox's design made me so disgusted that I don't think it's worth picking first. So, I guess i'll be going with Froakie...
On my second playthrough, i'll probably pick Finnekin and then give it an everstone once it hits its second stage. I LOVED its second stage; I thought the design was cool, and I loved how she used a wand.
In the silence of the night, I see you shine. http://i.imgur.com/i5bhlaY.jpg
I've always wanted to pick Chespin, and despite worrying when I saw Quilladin (I hate how it looks, especially the Sugimori art), Chesnaut is also coincidentally my favourite fully-evolved one, so I'm definitely happy with my decision.