IIRC, at the December NIH/CDC meeting Francis Collins suggested that the way to get to the bottom of the missing heritability, the common disease common variant hypothesis, gene-gene and gene-environment interactions, etc. etc. is to run a population-wide, 20-year longitudinal study in which genome-wide data and detailed environmental and behavioral minutiae were tracked for 100,000 participants.
The follow-up commenters starting with John Ioannidis each upped the sample size by an order of magnitude, until someone suggested that the entire U.S. population be sequenced, which it was then realized would require universal health care.
At that point, the meeting ended.