Here are my favorites:
Wizards and Warriors II – Mountain (http://www.youtube.com/watch?v=2ROQnr299Fo) (first song)
Suikoden – Distant Mountain (http://www.youtube.com/watch?v=47qlL8fvMcE)
Final Fantasy IV – Mt. Ordeals (http://www.youtube.com/watch?v=GHXrUUjlGjM)
Final Fantasy X – People of the North Pole (http://www.youtube.com/watch?v=ooA7CNbFne8)
Little Samson – Golem Theme (http://www.youtube.com/watch?v=ZQjMkxZE_zU)
Granada – Mountain Path (http://www.youtube.com/watch?v=MKwqUUC6OWI)
Blaster Master – Level 1 (http://www.youtube.com/watch?v=wpnQKIi64yE)
Chrono Trigger – Primitive Mountain (http://www.youtube.com/watch?v=mnumgbGko1E)
Final Fantasy VI – Mt. Koltz (http://www.youtube.com/watch?v=Z4ik1D3PzOA)
Robotrek – Hacker’s Base 1 (http://gh.ffshrine.org/soundtracks/2909) (download)
Super Mario 64 – Snow Mountain (http://www.youtube.com/watch?v=W9ivGbEbcPc)
Ys III – Entrance (http://www.youtube.com/watch?v=QSPcuZtynpY)
Mt. Rugged Theme – Paper Mario
I have loads more mountain themes I like, but at the moment those are all I can pick from the top of my head and I dont feel like browsing through all of my soundtracks to find some others 🙂
**edit** Cosmo Canyon – Final Fantasy VII
Others include:
Himalayas – Ducktales
Ronso Mountains(?) – Final Fantasy X
Towering Mountain – Lufia 2
Mt. Tamaranch – Link’s Awakening
YouTube – 3D Dot Game Heroes OST – Klovis Volcano (http://www.youtube.com/watch?v=nkFEbxKEjXY&feature=related)
Nobuo Uematsu – Mount Ordeals (FFIV), and Mount Koltz (FFVI)
EDIT: BAH Arthur, you sneak, you already beat me to them. 😛
In that case: the Red Mountain Zone track from Sonic Adventure (the exact track title name eludes me at the moment), even though it’s more a ‘volcano/lava’ type theme, it still suits the mountainous environment. 🙂
DK Mountain – Mario Kart: Double Dash!!
Death Mountain – The Legend of Zelda: Twilight Princess
Icicle Mountain – Super Smash Bros. Melee
Snowpeak – The Legend of Zelda: Twilight Princess