Deja-Vu by CSNY is great call -- somewhat underappreciated, but on the peak of rock definitely.
Willing to add some of my favorite debut picks:
Enya- Self titled album
Orchestral Maneuvers In the Dark -- Self-titled
Can -- Monster Movie
Kraftwerk -- Self-titled
Tangerine Dream -- Electronic Meditation
Residents -- Meet The Residents
Legendary Pink Dots -- Only Dreaming
This Mortal Coil -- It'll End in Tears
Cokteau Twins -- Garlands
Talking Heads -- 77
White Stripes -- The White Stripes
Dead Can Dance -- self titled