The top songs thing isn't really an accurate reflection of my favourite songs, so here's my top 15 in alphabetical order.
Haunting Birds by Agalloch from Of Stone, Wind, and Pillor
In the Shadow of Our Pale Companion by Agalloch from The Mantle
Love Psalm by Akira Yamaoka from Silent Hill 2 OST
Save Before You Quit by Akira Yamaoka from Silent Hill 3 Unreleased Tracks
Tender Sugar by Akira Yamaoka from Silent Hill 4: The Room
I'm Never Gonna Sleep Tonight by Asche & Spencer from Stay
Together We Will Live Forever by Clint Mansell from The Fountain OST
Homesick by The Cure from Disintegration
The Same Deep Water As You by The Cure from Disintegration
Death, Come Near Me by Draconian from Arcane Rain Fell
Shinkai by Konishi Kayo & Kondoo Yukio from Elfen Lied OST
Sear Me III by My Dying Bride from The Light at the End of the World
Bleak by Opeth from Blackwater Park
To Bid You Farewell by Opeth from Morningrise
Roads by Portishead from Dummy
Haunting Birds by Agalloch from Of Stone, Wind, and PillorIn the Shadow of Our Pale Companion by Agalloch from The MantleLove Psalm by Akira Yamaoka from Silent Hill 2 OSTSave Before You Quit by Akira Yamaoka from Silent Hill 3 Unreleased Tracks
Tender Sugar by Akira Yamaoka from Silent Hill 4: The RoomI'm Never Gonna Sleep Tonight by Asche & Spencer from Stay
Together We Will Live Forever by Clint Mansell from The Fountain OST
Homesick by The Cure from Disintegration
The Same Deep Water As You by The Cure from Disintegration
Death, Come Near Me by Draconian from Arcane Rain FellShinkai by Konishi Kayo & Kondoo Yukio from Elfen Lied OST
Sear Me III by My Dying Bride from The Light at the End of the WorldBleak by Opeth from Blackwater ParkTo Bid You Farewell by Opeth from MorningriseRoads by Portishead from Dummy