In Rock, Fireball, Machine Head, Made in Japan and that ‘In Concert’ album with the 69 and 72 BBC recordings and the purple cover are the core, and pretty amazing, LPs. Burn, Live in London, Who do We think we are and their self titled 3rd album make up their second tier. Powerhouse, the collection of Mk 2 outtakes, at a push. Machine head should be re-sequenced to put ‘When a blind man cries’ at the end of side 1.
Shades of Deep Purple is a good album, but sounds like a completely different band. The rest is second rate by comparison. If you want to hear Tommy Bolin, listen to Spectrum by Billy Cobham or Teaser.