Yeah while Waters rants could grate (the final cut springs to mind) the band did lose that something when he went,but hey ho they provided me with simply the best concert i'll ever see..the wall at earls court back in 1980,as a 14 year old lad i really couldnt grasp what the hell was going on but what a show..
As for albums for me at least Animals stands out alongside Meddle,echoes is simply one of the best songs ever made IMO,but of course dark side and wish you were here are great albums as well.
As for the Barrett era of the band,well it simply sounds dated now and frankly if he'd have been well enough to continue i dont think Floyd could have produced the later stuff,i listened to the piper at the gates of dawn a week or two back and as a curio,a snapshot of the summer of 1967 i suppose it gives a little insight to what was going on at that time,but musicly its very poor.