I don't think that's the point though ... I think it's the bands within this scene that are seen as classic albums, not the mainstream. The ones that in 10 years we'll be talking about like we do "Deja" and "Futures" and "is a Real Boy ..." now.
I get that part, but I still don't feel like the Menzingers album will hit that status really, but i guess that's just from my viewpoint
I'd say Japandroid - CR, Frank Turner - EKMB, Fleet Foxes - Helplessness Blues, Mansions - Dig Up Your Dead, Portugal. The Man - In The Mountains In The Clouds. I know it's soon but I'd throw Frightened Rabbit - Pedestrian Verse in there too it is just brilliant start to finish.
Out of these on the list, I really only agree with Separation. It honestly is still as fresh as it was the first time I listened it. Their next releases are going to be huge just based on hype alone. But if their newest split is any indication, the next album could easily be considered a "classic" in a few years too.
Some Nights definitely has potential staying power but at the same time I think it depends on their next move. They have tons of "newer" fans from this album who I think will be looking for the same sound again. Personally I love Aim & Ignite, I think that album would fit way better on a classics list. That album is nearly perfect, I still love it and listen to it all the time.