Best prospects: Pitchers or hitters?

As expected, I received a great deal of considered opinions about my last column, regarding the relative worth of hitting prospects and pitching prospects (I favored having young hitters). Here's a representative sample (and I wish I had the space for all the good ones):

Matt Galemmo: I read all of your stuff, and I am a huge fan. But your column about pitching prospects vs. hitting prospects was incomplete. You did well to prove that developing pitching is more risky (although this is not particularly insightful anymore) in the second half of the article, and alluded to how developing pitching may be more rewarding in the first half. But the article ended before you tied the halves together.

The question still remains: Is the reward worth the risk? Since most GMs would take the fifth-best pitcher over the fifth-best hitter in the majors, there clearly must be a line where pitchers are also more preferable in the minor leagues. And it seems that line gets harder to find as the players get younger. For example, I expect both Arizona and Boston would prefer to have the pitchers at this point in their careers, but maybe 1-2 seasons ago, that might be the opposite.