Winner
Diverse in Unity
I don't know, maybe actually learn to organize and coordinate long missions and live in space?
Oh, there is a LOT we can do on the Moon. Most important part is to build up industrial infrastructure that will aid us in further exploration of the Solar System.
Recently it was confirmed that the Moon has a lot of water near its poles. (Here's one good reason to land few geologists there to find out more.) If this water can be mined, and I see no reason why it shouldn't be possible, it can literally fuel further human expansion in space.
Launching anything from lunar surface into orbit is 22 times easier than launching it from the Earth. Thus, with relatively little effort, we could produce fuel on the Moon and then transport it to Earth-Moon Lagrange point(s) or the low-Earth orbit (LEO).
Of course there are other things you can produce - metals like aluminium, even platinum. Even if there was no water at all, lunar rocks are mostly oxygen, which makes up roughly 90% of rocket fuel mass. Moon is also a good place for space telescopes (no atmosphere), all kinds of geologic research and most importantly, a place very close to home where we can develop techniques necessary for living on other planetary bodies.
Another thing worth mentioning is that the proximity of Luna makes it easier to engage the private sector there. Once the initial infrastructure is set up by governmental space agencies, stuff like cargo/crew transportation, food production, mining, habitat construction, etc., can be outsourced to commercial subjects - and the governments would thus be free their hands to pursue the Mars programme, with the benefit of the experience and fuel gained on the Moon.
Mark my words: Ignoring the Moon will cost us all dearly.