Ok, I may have heard about it, but /a/ doesn't talk about it enough for me to make special note of it, much less set aside the time to watch it.
I have easily 200 hours of backlogged anime that I'm working my way through, and I'm adding to that constantly. Something has to have more going for it than being a "classic" to get added though.
"Classics" always have that whole nostalgia goggles thing going for them, and watching them after the fact usually leaves me thinking that their quality was grossly exaggerated. Not usually to the point where I purposely avoid watching them, but my skepticism is at its peak whenever someone recommends something that's a decade old.
There are probably lots of people here who have been frequenting /a/ for a long time that haven't seen a lot of what you might consider required viewing.