The Floyd you hear on the radio (ie Water's Floyd) and the Floyd you hear on this album are two different bands. The latter was the only Pink Floyd I had heard and for the most part I found it to be good, but this album is spectacular! There is nothing quite like it of this era- it's fun, it's silly, it's dark, it's whimsical, it's intense, it's raw, it's deep, it's up, it's down, it's upside down, buy it!
For me....it'll probably have to be "Animals", as it was my first proper entry into Pink Floyd. I'd heard the odd Floyd track, here and there....but when a friend sat me down, and played "Animals", it lead to me picking up virtually all their best albums.
Outside that personal attachment to "Animals".....then "Meddle" & "The Piper at the Gates of Dawn", tie for second place.