Not to go "Lord Zola" on everyone, but I decided to take a look at ages versus production for the 2012 stats. My population were those MLB players with 350+ AB for the year. There were 196 batters in that population (or about 31% of the players who had official AB last year). This is a good number to me because it will cover most of the players we recieved "benefit" from last year.
Of those players, I broke them into three general sub-categories predicated on age. The young blood (19-25, who make up 23% of the target population), the sweet spot (26-32, or 63%), and the Bengays (33+, or 14%).
As Doughboys labeled me (correctly), I am an AB guy. Can't drive in a run from the bench. So the question becomes, from within the target group, was one or the other more or less represented when it comes to total AB. The answer ended up being "no". Each grouping, within tenths of a percent, had equally distributed AB in relation to their percentage of the target population (i.e. the young bloods got 23% of the AB, the sweet spots 63%, et al).
So what did they do with their chances? The young bloods, in no real surprise, out performed in stolen bases by garnering 30% at the expense of the sweet spots (59%) and Bengays (11%). However, in the power categories, the sweet spots showed that the old adage about maturing into power is still true getting 66% of the HR and 65% of the RBI's, to the expense of the young bloods in both categories (21% and 21% respectively). Strangely enough, the Bengays proved there is still some in the tank and held their power numbers relative to their population (14% and 14% respectively).
In the Runs category, strangely enough, each category was equally represented in relation to their percentage of the target population. One more bit of power numerish. On average, the young bloods averaged 15.6 HR per player, the sweet spots 18.3, and the Bengays 16.9.
So, definitely go young when chasing speed, but don't go crazy because those guys in the prime of their careers (ages 26 to 32) still give you the best chance at power.
Need help with BA? Of course, you have to judge each player individually, but as a group, the young bloods had a collective 0.266 BA, the sweet spots 0.270, and the Bengays 0.275.
Go Old Dudes!

Baseball is a slow, boring, complex, cerebral game that doesn't lend itself to histrionics. You 'take in' a baseball game, something odd to say about a football or basketball game, with the clock running and the bodies flying.
Charles Krauthammer