Well, besides some of the obvious Pink Floyd stuff like Another Brick in the Wall (Pt. 2), Floyd also has some lesser known music that is very good. Check out the album- Obscured by Clouds- I recommend "Stay" and "Wot's... Uh the Deal?" The album- Meddle - has some decent stuff like "Fearless" and "A Pillow of Winds". "Green is the Colour", from More is good, as well as "If", "Fat Old Sun", and "Alan's Psychedelic Breakfast" from Atom Heart Mother. "Grantchester Meadows" is an awesome gem in the middle of the very strange album, Ummagumma. So even though The Dark Side of the Moon and The Wall are great, it's always good to check out the underrated albums because one may never know what they will find.
50's: elvis (though sensational did have a couple songs that werent recognized but were really nice); & james earl jones 60's:uhm not much of a sixties fan but definity isley brothers; beach boys;chicago... they have some really great songs ( my favorite is look away or your the inspiration) 70's: beatles; don mclean; stevie ray vaughn; golden earring; pink floyd;bob marley 80's: bruce springsteen; bob marley; queen; michael jackson 90's: not much of a classic rock era but still, if your looking for great songs from the bands im listening to most of them have work re-published into better versions in the 90's-00's era