Apologies for joining late and coming in swinging gents, a few thoughts:
I doubt there’ll ever be consensus on what constitutes ‘classic’, but I’m sure most of us would agree it goes beyond being well known and popular.
I don’t think the Classic Albums series is any guide. After all, they are the ones they can get the rights to, and my first point also applies.
For me there has to be an element of ‘game changer’ about it. So I would include:
Are You Experienced? Guitar was never the same again.
Van Halen. Guitar was never the same again.
DSOTM. Set the new bar for production and sound quality.
Sgt Pepper’s. Re-wrote pretty much the whole rule book.
None of them would make my favourite Top 10, but that’s a different issue.
I thought "Classic" means an album which stands the test of time, ie we are still listening to many years after release