Oh yeah, this is brilliant.
I've never even heard of this film, psychedelic cowboys you say? I gotta see it.
Speaking of, I'm quite partial to the El Topo OST, have you heard it? Great film too.
http://www.youtube.com/watch?v=jg__QfsPwaE
Other than that, early yakuza film soundtracks mean a lot to me, like Tokyo Drifter or the early Kitano films like Violent Cop or especially the soundtrack Joe Hisaishi did for Hana-bi.
http://www.youtube.com/watch?v=S5xolWSN2B4
http://www.youtube.com/watch?v=gFj_ja5b6QE
Not familiar with Diablo on that level but I definitely agree about Zelda and Pokémon, I recall Castlevania having a fucking cool soundtrack in the early games too.
Elder Scrolls for sure, not familiar enough with Dragon Age or Borderlands though, feel free to spam examples sometime.
By the way, which Shinobi game are we talking here? I'll have a look on youtube.