My favorite game OST is probably the work of Matt Uelman on the Diablo II soundtrack it's an award winning composition, also working on early world of warcraft and The TBC Expansion later moving on to the game torchlight, I highly reccomend it even if you don't have the game it's actually a decent piece of music.
for action game OST I would say it's goldeneye n64.
for action game OST I would say it's goldeneye n64.