songs that send a shiver down your spine

Emperor, at least on their first two albums, were the undisputed masters of the chill, especially "With Strength I Burn," off of Anthems. Burzum's "Hvis Lyset Tar Oss" is also chill-inducing.

Non-metallically speaking, later Swans (everything post-The Burning World), Floodland-era Sisters of Mercy, and Godspeed You! Black Emperor do it for me.

EDIT: Oh, and I almost forgot: the Angelic Process. Whether or not they're metal is debatable: I've seen people take both sides of the argument. However, their latest, Weighing Souls with Sand, especiall "Million Year Summer," never fails to give me the chills. Second that for "Coma Waering" off the album of the same name. Massive stuff!

EDIT EDIT: Goddamit, I keep forgetting stuff. Neurosis are great for the chill, what with their propensity for what I like to call "clench and release." A Sun that Never Sets is the ultimate in this regard.
 
Aye, South of Heaven is probably their most chilling album, in general.

I'd say so. It's the really trebley sound, and also that they discovered the volume knob and the incredible technique of sometimes not playing at 300mph to make the parts where they play at 300mph more hardcore. Also, Araya's lyrics come across clearer, making them creepier.
 
My Dying Bride - The Cry of Mankind
My Dying Bride - She is the Dark
My Dying Bride - A Kiss to Remember
My Dying Bride - For You
My Dying Bride - To Remain Tombless
My Dying Bride - The Snow in my Hand
 
At the moment I'm getting shivers from The Script for my Requium by Blind Guardian and anything from Kamelot's Epica and The Black Halo. Also Turisas: The Varangian Way (especially The Dnieper Rapids and Five Hundred and One, lately).

EDIT: Miklagad Overture, too.
 
Aye, South of Heaven is probably their most chilling album, in general.

Just noticed this reply, yeah I agree. There's something really cold about South of Heaven, it's definitely their darkest album. I remember thinking they were pure evil at the time. This was just before they went all basketball jerseys and tacky merch.