His progeny have been incredibly prolific. It's interesting that Bill Clinton knows his descent from Adams, but few genealogists have found out much about the "other lines", particularly the Church of the First Born part ~ but we know them well. Someday I suppose we'll pass some of that stuff around.
But I'll tell you, if you only have one famous ancestor, John Adams is someone to be proud of.
I figure you go back far enough I am descended from Charlemagne. After all there were only about 200 million people back then, he has a lot of descendants.