wOBA is something to pay attention to. It is a stat that synthesizes a player's offensive contributions into one number without some of the inherent flaws of something like OPS (which is adding 2 numbers with different denominators - easy to calculate but limited).
Using empirical data run values are calculated for various offensive outcomes (1b, 2b, 3b, hr, bb, ibb, roe, hbp, sb, cs) and then applied to a player's actual line. You add it all up and then divide by total plate appearances. The numbers scale to OBP so it is easy to interpret what is a good wOBA. The league average is usually around .333 or so (varies slightly by year).
The other thing you can do is then figure the runs a player contributes compared to an average player by taking the difference of a player's wOBA and the league wOBA and multiplying it by total plate appearances and dividing by 1.15.
For more info:
http://www.insidethebook.com/woba.shtml