I've heard many people talk about what's "classic" to them in terms of albums. What constitutes a "classic" album to you? Personally, the term classic album suggests that the album is perfect. Many people I know will say an album is classic, but then admit it has a bad song on it some stupid skits (IE, most "classic" rap albums). Sometimes they say a classic album can contain a bunch of utterly amazing songs, and a couple filler songs and still be considered perfect; I disagree. Paranoid by Black Sabbath contains some of the most amazing hard rock/metal (War Pigs, Paranoid, Iron Man, Planet Caravan) songs ever written, but it also has a couple meh songs. It's not perfect imo.
I'd say these are some classic albums that don't falter:
Led Zeppelin - II
Zeppelin's first album is one of the ultamite balls-to-the-wall rock out albums of all time, but with their second album the band took things to an entire new level. The album contains some hard rock anthems such as Whole Lotta Love, Heartbreak, and The Lemon Song, but what makes it brilliant is the more soft, warped songs that showed an entirely different side of the band. Thank You and Ramble On are amazing songs, and some of the band's best works. And of course, there's fucking
Moby Dick.
Pink Floyd - Dark Side of the Moon
I don't think I've ever heard an album better than this. The entire song has such a solid foundation melody, and each songs serves a purpose. The vocals on Great Gig in the Sky still gives me chills today; it reminds me of all the times I witnessed similar preformances at my grandma's black megachurch, or at funerals. The entire album seems to contain one thematic bassline that dictates the music, and this is best heard on Money or Any Color you Like. Time is still one of my favorite songs of all time as well. And is there any album that ends better than this one with Brain Damage/Eclipse? Utterly amazing.
Pink Floyd - Wish You Were Here

Another classic album, Wish You Were Here contains some of the best guitar-work I've ever heard. There are certain guitar riffs/solos/etc that seem to grab my soul (such as Little Wing, for instance), and the epic Shine On You Crazy Diamond does. The album also contains some brilliant lyrics, best seen on Have a Cigar and Welcom to the Machine; both songs vividly tell great, yet grimly warped, stories of the music industry and its victims. Overall it's just an amazing achievement.
Metallica - Master of Puppets
Even the most jaded fan can't deny that Master of Puppets is shere brilliance. The album mixes rapid fire riffs with more complex, haunting melodies than anything I've ever heard before. From the minute Battery's wicked riffs kick in, it's clear you're in for an orgasmic kick to the face. The imagery in the title song is just the beginning of the madness though: the entire album contains great, meaningful lyrics. Every song is an anthem, every song contains a classic guitar solo, and every song kicks ass. Period.
Nas - Illmatic
This is the first rap album on my list for a reason. My problem with most so called "classic" rap albums is that they contain stupid skits, filler songs, or terrible guest appearances. Illmatic doesn't have any of those problems. While many of Tupac and Biggie's albums have superior songs on them, they're held down by some of the problems I mentioned above. Nas' flow is nigh untouchable, and he displays great lyrical ability. This is best seen on this album, on which he spits over efficient, yet brilliant beats (non of which are overproduced or flashy). One Love has a very simplistic beat, yet it's better than most beats I hear today. It's also worth pointing out that most of the songs don't have a traditional chorus; although The World is Your contains a rather off key sung chorus, it's saved by some awesome verses. This should be the blueprint on how to make a classic rap album.
I'm tired, so I won't list anymore right now. Please take time to list some albums you feel are truly "classic" in terms of perfection.