Rob gave me the idea (from the amazing Amber game he runs) for putting out an official play list. So here it is; I wouldn't look for too many literal clues from any of the lyrics. I reserve the right to add more or to change whatever the hell I want. You can listen to most of these below thanks to lala, though some of them aren't yet available.
Imago's theme song:
The Ambitions Are by Golden Palominos featuring Nicole Blackman
(Used by generous permission of Ms. Blackman. Thank you.)
General theme music of Imago:
Angel by Belly
Fly Away by Poe
in this twilight by Nine Inch Nails
Land of Sunshine by Faith No More
Map of the Problematique by Muse
No Signs of Pain by Azure Ray
Other World by Noise Unit
Scare Goat by MC Frontalot
Sea Song by Lisa Hannigan
Slow Motion by Third Eye Blind
Song to the Siren by This Mortal Coil
The Bells by I:Scintilla
Trickster by Kidneythieves
Twenty Years by Placebo
Wicked Days by Android Lust
NPC theme songs: (each is specific to a character - not every NPC has a theme song)
Aenima by Tool
Blood Of Me by Heather Nova
Center of the Sun by Conjure One (feat. Poe)
Cernunnos by Faith and the Muse
Diluadid by The Mountain Goats
Doll-Dagga Buzz-Buzz Ziggety-Zag by Marilyn Manson
Dream Ridiculous Implausible by Jane Jensen
God Save The Queen by The Sex Pistols
Flower by Liz Phair
Tragic Figure by Assemblage 23
Incantation by Delerium (feat. Kristy Thirsk)
Joy by VNV Nation
Limp by Fiona Apple
My Sins by Lennon
Pet by A Perfect Circle
Shine by Anna Nalick
So What by Ministry
Star 24 (No Apologies) by Jakalope
Music used during actual games / episodes:
Swing That Thing by Johnny Ferreira
Around The World by Natalie Brown
The Last Saskatchewan Pirate by The Pubcrawlers
a sample of what i can do by DJ Eclipso
Methamphetamin by operaEftos
I Am Blank (Nothing) by J.E.L.L.i.
A Sample of What I Can Do by Thank DJ Eclipso
My Immortal by The Outsyder