In light of what Craig suggested I'll skip giving too much spotlight on Simon and Garfunkel (Wednesday 3AM) or Bob Dylan (everything from 64-69 and then some). Instead:
Frances the Mute - The Mars VoltaIt's The Mars Volta's second album, and it was the first one from them that I listened to. It introduced a whole new genre of possibilities that I at first just could not get in to. A couple years later I revisited the album with more musical appreciation and found myself enjoying it from beginning to end. It's a musical novel that pulls you in with Cedric's insane vocal obscurities and Lopez' intensely distorted guitar work. John Frusciante and Flea from Red Hot Chili Peppers make special appearances with some guitar solos, bass bridges and even trumpet work.
Relationship of Command - At the Drive-In OK, so I heard about these guys from Cedric Zavala and Omar Lopez' earlier projects prior to forming The Mars Volta. That said, they've got a very different sound in At the Drive-In, with Cedric adopting a more post-hardcore/punk vocal. The entire album save for a few breaks is very fast-paced and refined, which is a different pace than their early almost lo-fi punk albums. I find myself listening to this album a lot lately, and as a very random inclusion, Iggy Pop makes two cameos on it.
The DrumsThis self-titled premier album from the indie group The Drums is a good change of pace from the other stuff. They adopt a surf pop/quirky indie sound that radiates a warmth and calmness that makes you appreciate the beach life.