Our friends at the SNTA have a nice presentation promoting how well syndicated shows did in June and July (PDF download) and though it's not surprising, it is still impressive to see Family Guy's dominance with all the youth demos we normally track (18-34, and 18-49). Two and a Half Men is a god among syndicated shows as well, but with younger viewers (18-24) Family Guy outperformed Men by 100%!
Also, we rarely see any C3 information (live+3 days commercial viewing) and the ratings in the presentation above are C3 averages. This makes it hard for us to compare to specific broadcasts or cable shows because we never see the C3 information, but it was still interesting to look through the presentation.
Because of the way syndicated numbers are reported (they lag, and there is no overnight reporting) and even the way the shows air, which is not necessarily the same time everywhere, we don't wind up spending much time focusing on syndicated ratings, but when it comes to ratings, syndicated shows are a big, big deal.