Time is a stereotypical choice, but it's stereotypical for a good reason. That said, I have such a soft spot for Nobody Home.
Meddle is great, it was the first of Pink Floyd that I discovered beyond Dark Side of the Moon and the hits played endlessly on classic rock stations. When I was in college and felt like I needed to take a nap, I would instead lay down in the dark and put on "Echoes". That song takes you on a journey like few can.
I used to always answer this question with "Arnold Layne", because it would break people's brains. The Syd Barrett era of Pink Floyd was a period of time where they had no specific identity or sound, so they experimented, threw shit at the wall, and saw what stuck. Accidents led to interesting journeys... But when people ask about Pink Floyd, they aren't talking about the Syd Barrett era. And I truly can't think of a more finely structured PF song than "Welcome to the Machine." That song gave permission to so many artists to look outside of the drums/bass/guitar/(sometimes keyboards) paradigm, and bring in ambient sounds to tell a deeper story... Love that track.
It's a cover, but I spent months listening to Us and Them: Symphonic Pink Floyd and think everyone should give it a listen. Also, not answering the question really but: Does anybody else get the same frisson from this shot in Live at Pompeii? I would love to have that as some sort of looping live wallpaper on mobile.
Man, that is such a difficult choice to make. My favourite album is The Wall, with Goodby Blue Sky probably as my favourite track and Run Like Hell as a power song runner-up. Google Play Music however tells me that I listen to Dogs most, followed by Summer '68. But I also really like Great Gig in the Sky, Keep Talking and Time. And the Pulse-version of Sorrow is just amaaazing. Concluding, is 'most of them' a good answer?
Nice. I had forgotten about that since I hadn't heard it in so long. While I hate to pick favorites, I really like this song as almost no one has heard it and it doesn't sound like most people expect PF to sound. It is fun. If I was a stripper this would be my song.