Hrm... it lets you sort by post count and by reputation, but it doesn't show either one in the list.
I'm beginning to wonder what the person who redesigned the forum software was smoking when they decided to release the new version.. Almost every major feature has an unfinished feel to it....
There's a Sort By button that lets you sort the list by post count which will give you the Overall Top Posters list, but it doesn't actually show the post count. If you hover the mouse over each name in the list though the post count is listed in the popup.