Post-National dex I'll probably have Feraligator follow me. Then I'll let my favorite pokemon Swampert follow me! Or maybe Luxray. Then again I'll probably just end up switching it a bunch of time. I think the follow feature is going to end up being HM based. Just a thought...
I would love to train up a Squirtle all the way through Blastoise and have it follow me the whole time, Post National Dex anyway. Pre-National Dex Im gonna have Totodile and his evo's follow me. But I also have a Gallade and Manectric that O want to transfer over from Pt that might follow me as well
I'll probably switch it periodically. Although I definitely want to see what Wailord looks like. Maybe I'll have out whichever Pokemon I'm training at the moment.