If we're counting visual novels as games then definitely Saya no Uta. Even though it only had a handful of tracks, there were some beautiful pieces. This one in particular is one of my favourite pieces of all time.
Hotline Miami, and Dark Souls have some pretty nice OSTs. But the best hands down is Fallout 3, and New Vegas. Also for T.V shows, i would pick Fargo (Murder and snowy cheerful music is pretty grand), and then Samurai Champloo.