I wouldn't call Floyd the best ethereal sound, since there's better out there. Listen to Klaus Schulze for some of that. But I think their most spacy sound to me comes from Echoes.
I don't know if some of you have heard of it, but if you haven't heard "The Nightwatch", I highly recommend the album. It's a live album that was recorded during the Larks' tour. It's excellent and well worth it.
I always found it amazing that that little ball was able to withstand thousands of asteroids hitting it when we had an asteroid belt some 50 billion years ago. If it can take it....I think the Earth can, we can rebuild!
Peter Green was a pretty great blues guitarist before he went crazy. His work with Mayall is pretty great too.
Then Play On is probably the best other than Mr. Wonderful, for me anyways.
Don't care for Mac outside of Peter Green. Sure some of the songs sound the same with Peter Green, but I do love my blues rock. Plus, I can't stand Go Your Own Way and Don't Stop. End of story.