Well, since Pink Floyd is my favorite band of all time, I'm going to recommend listening to:
~Meddle **
~Atom Heart Mother **
~The Division Bell **
~Obscured by Clouds
~Pulse (live)**
~More
~Momentary Lapse of Reason **
~Delicate Sound of Thunder (live)
~Relics (compilation album)
~Saucerful of Secrets
~Piper at the Gates of Dawn
~The Final Cut

**= Must have