The golden age is always in the past it seems. I can't think of one "best poster" who is gone myself, if by "best" one means posters who post useful information and research, and civilly engage in the sharing of ideas and discussion, rather than personalities. No doubt there are some who I don't know or can't recall, but just why they chose to move on to other endeavors could be for a host of reasons.
JMO.
The golden age of FR was over by 1998. By the time I registered, all the good posters had left in a huff.