I think my favourite game music is the Lunar the Silver Star Story first game one! Luna's voice is amazing! <3
I don't really remember the music that much from the Lunar series... all that I remember is how bloody awesome the games were. Vastly underrated. especially the Sega CD versions, they were by far two of the greatest RPG's ever made.
As for my favorite game music... Of course anything Final Fantasy. Thats pretty much a no brainer. However, I would have to say that I'm pretty partial towards any classic NES game. Some of it probably has to do with the nostalgic feeling one gets when they hear the tunes as they tend take one back to "the simpler" times of when one was a kid. But mostly because they were so simple. Whether it be Super Mario Bros, Zelda, Contra, Castlevania, Metroid etc. the list just goes on an on. The music stays in your head. Who now can't hum or imagine the music to lets say Super Mario Bros?... No one, and just that speaks for the brilliance of it
Speaking of Castlevania... Not only does it remind me that I have to go buy a DS so that I can play Order of Ecclesia but I can't forget about SOTN(Symphony of the Night). By far one of the greatest composed scores for a video game ever. The classical style music fit the story so perfectly. I don't really know what else to say about it other then its brilliant.