Forty years is a reasonable long period of time to judge or rate a record: to check how good it behaved throughout the decades, if it has influenced other works -although I believe that's not so important, since it's always been about how much it influenced you-, and maybe to drill down some melody we may have been humming along all this time.
Records like Dark Side Of The Moon are for some collectors like for normal people is to have food in the table or to own a car. You have to have it or else your life is worthless. Every once in a while getting an additional copy is good for you. With four decades on its shoulders and so many cultural changes that have happened since 1973, the collective sub-conscious has kind of forgotten how astonishing and groundbreaking this production is.
Darky owes much from its success to the conditions it was recorded. London's Abbey Road was the studio, Alan Parsons the main engineer (who later complained of not making any royalties out of this album), and the four members of the band were the actual producers. They risked everything and they got what they deserved: The permanency of the album on Billboard's Top 200 albums from 1973 until 1988 (I personally bought the Peruvian cassette for the first time one year later).
Still today, it's one of the best selling compact discs on Amazon.com. It's a record each new generation has to discover, and it is for that reason that the album will never leave, just like the Beatles' or Mozart's music.
In a sequence of nine (or ten) tracks, lyricist Roger Waters pens the story of a man (you or I) obsessing with time slowly pushing him toward his death. "Breathe" and "Time" are written almost in the same moderate beat. Between them, "On The Run", an intricate game of synthesizers, heartbeats and airport sounds where airplanes take off and crash. Richard Wright, the keyboard player, executes an instrumental called "Great Gig In the Sky", based on the ancient Egyptians' idea of the chariot that takes the dead to Paradise. Did I say ancient Egyptians? See the pyramids in the inner sleeve of the CD. See the pyramidal prism that decomposes the white light.
Ummagumma (Harvest, 1969): Still, the most spacey record of the sixties. Out of this Solar System.
Wish You Were Here (Columbia, 1975): A homage to guitar-vocalist-songwriter-leader of 1966 and 1967's Pink Floyd, Syd Barrett. Gilmour and Waters ask him to come back and join the band. But two guitars can't sound in the same amp, or can they?
Animals (Columbia, 1977): They got to be crazy. The ultimate conceptual album, the beginning of the end. In 2008 it became the unofficial anthem of the economy meltdown.
A Collection of Great Dance Songs (Columbia, 1981): In one record, the six most popular Pink Floyd songs. Adorable: "Money" played solely by Gilmour because EMI refused to give the song to Columbia.
The Wall (Columbia, 1979): the kick in the ass, from Pink Floyd to all the Punk generation. With lots of love.
Echoes (Capitol, 2001): Essential Pink Floyd, sequenced by Gilmour and Waters. Like previous albums, a tribute to the eternal Syd Barrett.