As a general rule, yes OBP is greater than SLG, but that is not always the case. Here is how I view the greater need in a lineup. 1. OBP- is the obvious choice here 2. OBP- these two are the table setters and need to get on-base 3. You need a balance here, I would say they are equally important here. 4. SLG- is going to win out here, ideally you have both, but if I had to choose its SLG. 5. SLG- same as 4, these should be your big power guys (Carlos Lee and ARAM would be a good example at 4 or 5) 6. OBP- you still want a guy with pop here, but OBP is more important 7. OBP- 7-8 are probably not going to be great hitters, but I would rather have someone get on-base to extend the inning. 8. OBP- want this guy to get OB so the pitcher bats and extend the inning 9. pitcher- just hope they do something! Why are you choosing one or the other? You need the best blend. OBP is a little more valuable, but you need both. If you do have a guy who isn't any good in one area, then he better be absolutely fantastic in the other. That is why Pierre hurts the team so much. Not only is he really bad with SLG, his OBP stinks. He's rarely been close to great in that department.