Good column in the San Francisco Chronicle by Susan Slusser explaining how the A's have gone from targeting college pitchers in the draft to high school ones. (Hat tip Kevin Kaduk (Big League Stew on Yahoo! Sports).
The point is that Billy Beane, used to target more polished college hurlers who were closer to the big leagues and carried less risk, but because other teams caught on, there was less value to be had there, so he turned his focus to high school pitchers. In other words, the value lies where the demand is low. To be a good GM or fantasy owner, you have to take the value where it comes to you.
So if everyone's spending on top prospects, target players in their 30s. If everyone's paying big bucks for position scarcity, draft some rock solid outfielders and cornermen. And if people are overpaying for hitting generally, get a rock solid pitching staff for cheap. The only way to do this is to be flexible going into your draft - don't be too wedded to pre-draft values or a pre-set strategy.