The music during the chestburster/discovery of Shaw's body is so beautiful, it actually brings tears to my eyes when I watch that scene. I'm sure if I watch it on mute, I might giggle at the silliness of the Oscar statuette alien conducting a symphony, but the entire composition is quite effective.
I also love David playing the Prometheus theme on the flute because it recontextualizes that music, takes away its optimism and wonder, and makes it a f**ked up tribute to Shaw composed by David, puts him in control of the narrative all along. Chilling, and very clever.