There are just 3 "questionable" albums and it depends on PERSONAL TASTE, you know, it's not a fact. Fans are always divided when talking of these particular albums.

They are:
Ummagumma studio
The Final Cut
A Momentary Lapse Of Reason

All the rest is "must have", and IMO, even these three albums are well worth your money. All I can say is listen and judge for yourself. Enjoy.

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"Don't you know there ain't no devil, it's just god when he's drunk." Tom Waits