Okay, this seems like a pretty obvious one due the the unimaginable inconvenience of having feet for hands.
Hands for feet seems like the clear choice. However, before you go rushing into your decision, consider a life spent walking on a pair of hands.
Human feet have evolved especially to enable us to walk bipedally. Before that, our feet looked much more like those of modern-day apes - they were much more flexible and even had opposable toes. This allowed us to grasp things and climb trees with ease, but the catch is that they're not so hot for walking.
You ever wondered with the other apes aren't skipping around on two feet? Our feet have adapted for walking by developing stiff ligaments in the middle, this gives us balance and stability whilst improving walking efficiency. Our short, stubby toes are also much tougher than our delicate, spindly fingers.
Hands, on the other, er, hand, are designed for fine, delicate movements, more so than our primate cousins, they're certainly not robust enough to haul your great carcass around all day. This delicacy, combined with their frankly unstable nature, would mean that hands would actually make extremely poor substitutes for feet.
All this said, feet for hands would well and truly suck. Maybe the obvious choice is the best in this case.
Verdict: Hands For Feet.