Personal list:

Bothy Band 1st album
Planxty 1st album
Chieftains 3
Tommy Potts, 'The Liffey Banks'
Boys of the Lough 1st
Liege & Lief
'Hark The Village Wait', Steeleye
'Pour Down Like Silver', Richard and Linda Thompson
'Kind of Blue', Miles Davis (play it after any of the above and you'll see what I mean)
'A Love Supreme', John Coltrane

Etc, etc.