Shame you closed the poll. I'd have voted for Team Magma. I don't agree with their goals, but I have a fascination with plate tectonics, in particular volcanic activity. So I'd join their team just to get into their secret base. Of course, I'd want slightly different pokémon, i.e. my trusty Swampert, which I could justify by claiming it's the fire safety department xD.
Their uniform is one of the best, too. It's just hoodies, long shorts and boots of some sort. Not too outlandish, not too weird, uncomfortable or inpractical in appearance either.
Overall, yes, I'd join Team Magma.