sonsofsamhorn.net has probably the best discourse of any board I've ever seen, but it's complicated to get onto the main board. You start out as a lurker status and have to be hand chosen by the mods to graduate to the real board based on your posts. They have some heavy statistical analysis. Pretty much everybody is into sabermetrics over there. It's a good board to read because it's so informative, but if you're looking to post a lot then try those other boards since it's not too easy to graduate from lurker status.