Racing quad! It's new, fun, cheap. Everyone is out there building AP quads so it would be fun to do something a bit different and really kick off that part of this forum. The troop carrier does sound good though....
I would vote for the Hovership since it's 3d printed. I bought one last week that I am assembling now with a Naze32 and a mobius for my recording camera. if you group build a 250 racer you will document the racer and fpv in general. I used the group build thread when I built my first quad this year and I still refer to it once in a while.