Great, great stat for measuring true offensive contribution.....
WPA - Win Probability Added
Using data from the last 35 years, they have determined the probability of a team winning based on home/road, inning, outs, base runners, and score differential for every possible situation. The way this stat works is it measures how much each players' AB changes the probability. For example, when Youk leads the game off in Fenway (home team) the win probability is 0.591. If he singles, the win probability goes from .591 to .630, so he raised the win probability by .039. This is the first stat I've seen that truly measures the relative worth of each in game event.
Situational Win Probability can be found here:
Win Expectancy Finder
WPA is here:
Fan Graphs -- click on the teams button at the top of the page to see the stats for each player
It works for pitchers too. The final WPA sum is multiplied by 100 to make it a percentage.