I'm 39 and grew up listening to the Archers, as did my dad. My earliest actual plot memories are of Nelson Gabriel's wine bar, and Mark Hebden and the robbery in the shop. I also have vague memories of a flood and of the Grundies (or possibly other yokielish characters) going on a trip to France. I listened all through university, where Northernlurker broke the news of John Archer's death, as I'd been up all night writing an essay and had missed the crucial episode.
My favourite thing that no one else remembers is the years when all the parts in the Christmas panto went to non speaking characters.