well, provided that the resources are there...
A. refueling stop for outbound-to-mars shuttles and other long range trips
B. a ready source of concrete.... for building habitats?
C. a militarily advantageous position... the 'high ground'
D. a population of humans that could actually be quarantined effectively, should there be an outbreak of biotech warfare...
E. tourism - who wouldn't like to climb inside the apollo lander on the moon?
heinlein thought the moon could be colonized from inside, since its basically a huge rock the most widely-available material is duh- rock, which makes a perfect radiation/vacuum tight cave. solar panels on the surface would generate light inside for plants, and the resulting low-grav yield crops would help to feed earth, who would keep the moon supplied with nutrients and water(crops are dehydrated before shipping). as far as who to colonize it, i think we should send our best and brightest - all the CEOs, top-level gov't officials, and religious figureheads could be put on a rocket and given a one-way ticket to 20 years hard labor, digging tunnels. =)