I suggest an additional statistic: the count of post made in the off topic forum.
Any n00b with even a mild interest in politics and religion will quickly have a booming post count from his participation in the OT forum, but this has absolutely no value for the rest of the site. (where we discuss civilization games and such)
Or maybe even better:
A post count per forum!
It works like this:
In the user profile, all statistics are visible.
But when viewing a thread, only 2 are visible, the total post count, just like it is already, plus the posts made in the forum the current thread belongs too.
Yeah, I just love statistics, but only if they are accurate and refined. A single total post count means something, but very little, with more data, we can make more conclusions.
So here is an other idea: A lurk counter!
This records how many times a forum member viewed a certain forum, or a thread in a forum. (yes, also per forum)
And a counter for how many new threads where started by a forum member. (also per forum)