Etrian odyssey untold 1&2, all the music in those games are amazing
Final Fantasy series:
I of course love the final fantasy hits, but Ill at some of my other personal faves, most notabily from Zone of the Enders and Noir~
The songs from nier are sung in a made up language, which I thought was amazing. Cant wait to play the new one on the PS4~
Not sure if anyone has said it already but Ar no Surge has some really beautiful songs, and the vocals are amazing.
I have to go with songs from Final Fantasy on this one. To me there's always at least two or three songs that are great in each game, but here are some that stand out to me the most.
Metal gear solid: sons of liberty.
I have best based on genres but if I had to pick one, it'll be Guilty Gear X. I can rock out to they anytime.
Alone in the Dark, Blue Sky Blue Water, No Mercy, Awe of She, and Meet Again (Guilty Gear X 1.5) are pretty solid tracks.
Guilty Gear XX (Korean Version) is number 2.
To The Moon: Born a Stranger - One of the very few games that literally made me burst into tears it's that incredibly emotional and this short track is easily one of my favourites <3
I highly recommend listening to the whole soundtrack, it's beautiful stuff.