I like Obscured by Couds, Meddle, DSOTM, WYWH, Animals, The Wall...
But one of my all time favs is The Division Bell. Most of the music is quite good and the lyrics are unbelievably emotional as much of it is about Dave Gilmour's relationships- most notably with Roger Waters and Syd Barrett. Almost every single song references Roger Waters or Syd, or the emotions of the band Pink Floyd and it's history. In fact, it's been said there is a bit of an enigma within the album, a puzzle of sorts, within the music, lyrics and the booklet artwork. It actually became a convaluted thing that lasted for a few years where hundreds of people on the alt.Pink Floyd newsgroup were involved in trying to figure this "enigma" out that led to painstaking and compulsive analysis of The Division Bell. In fact, an anonymous poster named "Publius" began posting clues to the newsgroup offering guidance to the solution of the enigma. Many believe it was Nick Mason, believe it or not, and to prove that Publius was not a farce he said to watch the writing on the circular screen during a live Pay Per View concert at Earls Court (later made a video) and his trust would be proven. Sure enough, and the video is out there for anyone to check it out, the words "Publius Enigma" were spelled out in a bank of lights at the front of the stage before "Keep Talking."
The whole Enigma thing faded away eventually, many think it was Nick Mason playing games driven by his fascination of how well the Division Bell came together as a concept album that was not completely planned before hand. The concept was of "Communication." Publius always said "Keep Talking" at the end of his posts. And that's what happened. Through all the communication it made people realize the importance of communication and it revealed many personal things of Dave Gilmours struggle with broken communication with his two long lost friends. But most surprisingly of all it made people realize how much depth the Division Bell truly had and with that it became a personal favorite of many thereafter.