You can find all sorts of great tracks online.
The best place I have found is Galbadia Hotel

Click here for the Official Dungeons and Dragons Soundtrack mp3s

Click here for the Eberron Soundtrack mp3s

Click here for the Elder Scrolls Oblivion Soundtrack mp3s

Songs good for non-combat generally spooky:

Official Dungeons and Dragons Soundtrack - Craft Of The Wizard
Official Dungeons and Dragons Soundtrack - Prelude
Official Dungeons and Dragons Soundtrack - Ruins Of Bone Hill
Official Dungeons and Dragons Soundtrack - Stealth And Cunning
Official Dungeons and Dragons Soundtrack - The Fens Of Sargath

Eberron Soundtrack - Exploring Xen'drik

The Elder Scrolls Oblivion Soundtrack - Wind from the depths
The Elder Scrolls Oblivion Soundtrack - Tension
The Elder Scrolls Oblivion Soundtrack - Ancient sorrow
The Elder Scrolls Oblivion Soundtrack - Auriel's ascension
The Elder Scrolls Oblivion Soundtrack - Unmarked stone
The Elder Scrolls Oblivion Soundtrack - Deep waters

Songs good for Dramatic Combat Scenes:

Eberron Soundtrack - Cut to the Chase

Official Dungeons and Dragons Soundtrack - Army Of The Dead
Official Dungeons and Dragons Soundtrack - Beasts Of The Borderlands
Official Dungeons and Dragons Soundtrack - Deep Trouble
Official Dungeons and Dragons Soundtrack - Final Confrontation
Official Dungeons and Dragons Soundtrack - Heroes' Valor
Official Dungeons and Dragons Soundtrack - How Strange
Official Dungeons and Dragons Soundtrack - Ride To Destiny
Official Dungeons and Dragons Soundtrack - Skirmish
Official Dungeons and Dragons Soundtrack - Troubled Times