I had a friend who really enjoyed the music backing the Diablo 3 trailer, and that of the Wrath of the Lich King trailer. Outside these trailers or movie soundtracks is there anywhere you can find music using this sort of style.
I’m not familiar with that particular music, but most of the Blizzard music I’ve heard seems to hark back to fantasy movie scores which in turn is fairly heavily influenced by composers like Holst and Wagner. So potentially he might want to give that stuff a listen…
Do you have links to the trailers in question?
You can buy the various soundtracks to the Wow games from Blizzard, either from them or through Itunes. There’s also the Echoes of War CD that you can get which is a reorchestration combining themes from multiple Blizzard games into single pieces.
And, you can also purchase the CDs done by the Video Games Live! concert series.
As for other music like Blizzard music, I would definitely go with Gordon’s recommendations, and perhaps add in Igor Stravinsky and/or Modest Mussorgsky.
Your friend has a hard-on for ethnic wailing, and will probably need to be put down. However, if he can be convinced to let that go he may find that he enjoys E.S. Posthumus.
Also, check out Corner Stone Cues and Immediate Music.