This site's opinion (not from the Echoes FAQ)
This comes up all the time, especially when new people join (Echoes) and want to voice their opinions. The problem with this question is that everyone has their own thoughts on the matter, and that these thoughts are entirely subjective. Without going into any details, any pros and/or cons of either Syd's, Waters' or Gilmour's writing, singing, or playing styles, and without delving into the personalities of different members of the band or the concepts they provided or the concerts they performed, I'm just going to say that everyone likes or dislikes any particular version of Floyd or the solo artists for strictly personal reasons, and trying to convince anyone to change these likes is going to be a futile effort.
Posting on this subject in newsgroups and especially on Echoes is highly frowned upon.
Actually, the best by far is the Pink Floyd that consisted of Roger, Dave, Richard, and Nick (well, maybe Nick didn't matter) This combination created the best albums: musically, lyrically, conceptually, and profitably. Of all the Pink Floyd albums out there, the great majority will name as their favorite album one of big four (DSotM, Animals, WYWH, or The Wall).