Twilight: (DTS-HD MA 5.1) - Tier 1
This was a tough movie to rank for me because this movie has very little in the way of dramatic sound effects. Nada, nothing, zippo. No real LFE, not much surround panning, not much of anything really. On the scale of impressive demo worthy material, this movie is certainly not a Tier 0 movie. However, this movie doesn't really require much in the way of effects because it is not an action movie.
However, the subtle music in this movie is extremely well presented. Think of hi-res music you might download. Never harsh, just light, airy, and very clean. Take for example the scene where the two listen to Debussy. It almost puts you to sleep, but the music is rendered wonderfully. The piano has great body. Again, this is very very subtle. The dialog is wonderfully clear as well.
So despite the lack of almost any effects, I'd rate the quality of what IS there Tier 0, as compared to the music in other movies that are Tier 0. If impressive effects and more surround are a factor for you, then I'd downgrade this to Tier 1 or even Tier 2.
I just have to give this Tier 1 because of the lack of effects. However, the music that is there is truly nicely mastered.