Last thread I'm starting today, unless otherwise requested. Caves are fair game in this thread too.

Metroid - Pretty much all of the tracks work
SMB - 1,2, & 3
Goron Cave/Mines - Misc Zelda
Kid Icarus - Underworld

Once again I'm drawing a blank for the rest of my favorites. Post away.
-The Dude-

Symphony of the Night - Underground Mines
Super Castlevania - Laboratory

Chrono Trigger - Undersea Palace (http://www.youtube.com/watch?v=iSP-_hNQyYs)
Chrono Cross - Ghost's Island (http://www.youtube.com/watch?v=k85Pnjq0F0w)
Legend of Zelda: A Link to the Past - Cave (http://www.youtube.com/watch?v=e2wLk4K-jlU)
Donkey Kong Country - Life in the Mines (http://www.youtube.com/watch?v=BhuupicYzog)
DuckTales - African Mines (http://www.youtube.com/watch?v=lnzVZozWlR0)
TMNT II: The Arcade Game - Technodrome (http://www.youtube.com/watch?v=9NHC36aOcH0)
Monkey Island 2 - The Crypt/Rapp Scallion (http://www.youtube.com/watch?v=rIRT9xw4nuw)
Earthbound - The Cavern of Ages (http://www.youtube.com/watch?v=-1lZswESsC8)
Final Fantasy IV - Land of the Dwarves (http://www.youtube.com/watch?v=W6cgYMtuSt0)
Final Fantasy VI - The Mines of Narshe (http://www.youtube.com/watch?v=FpsgQvMnaL0)
Breath of Fire - In a Cave (http://www.youtube.com/watch?v=pcYcSgfWGO4)
Breath of Fire - Romero Cave (http://www.youtube.com/watch?v=XiVQD-ZIefY)
Breath of Fire V - Lifeline (http://www.youtube.com/watch?v=aIFHMGw2RTk)
Klonoa - Blue Cave Echo (http://www.youtube.com/watch?v=i9lOa4JOUqU)
Lunar SSSC - Mysterious Cave (http://www.youtube.com/watch?v=O6s1-N-MzKU)
Little Samson - Golem's Theme (http://www.youtube.com/watch?v=ZQjMkxZE_zU)
Cave Story - Geothermal (http://www.youtube.com/watch?v=_JCxwocVoP4)
Dark Cloud - Cave of the Djinni (http://www.youtube.com/watch?v=cI_L_DXGDJQ)
Suikoden II - Labyrinth (http://www.youtube.com/watch?v=ZbIjiUBaHFs)
Terranigma - Underworld (http://www.youtube.com/watch?v=S3mqIDAVObA)
Most of the Blaster Master soundtrack (Thread 34462) (download)
Most of the Super Metroid soundtrack (Thread 39734) (download)

Could someone set up links for all these songs for downloading? That would be awesome.