Love instrumental rock. (although have to be in the right mood for it) A couple of favs:

Agalloch- The Hawthorne Passage, Sowilo Rune
Baroness- Bullhead’s Lament
Devin Townsend- Down and under
Dream Theater- Hell’s Kitchen, Overture 1928
Evpatoria Report- Taijin Kyofusho
Explosions in the Sky- Your hand in mine, Catastrophe and the Cure
Godspeed You! Black Emperor- 09-15-00
Hammock- Floating away in every direction
Jakob- Malachite
Laura- Ariadne, Levodopa, Non Servium, Every Light
Living End- Closing In
Pain of Salvation- Dryad of the woods
Pelican- Far from fields, city of echoes
Porcupine Tree- wedding nails
Red Sparowes- Alone and Unaware…
Rush- Leave that thing alone
This will destroy you- There are some remedies worse than disease
65daysofstatic- radio protector
Some of those are pretty mellow.