The music attached to a film creates the environment, I believe, moreso than the literal environment depicted through the visuals...
I have always loved the soundtrack to American Beauty. Originally, I had the two well-known tracks "Any Other Name" and "Dead Already" featuring on a soundtracks compilation. But I still wanted more. I then found a soundtrack in a charity shop for a couple-o-quid and realised that only those two tracks from Newmans score featured on this soundtrack - the rest of the tracks consisting of the artists featured - such as The Who and Free. Don't get me wrong, I like the tracks, but it wasn't Thomas Newman's score.
Eventually, I hunted the score itself down and - because you can find the aforementioned tracks very easily, I have have chosen tracks which only feature on the score soundtrack
5. Mental Boy - This track begins with a sinister sound that is unsettling before the piano softly plays a melody that is innocent and sensitive. A great example of the balance Mendes tries to create in the film between innocence and deeply unsettling problems that affect families.
11. Weirdest Home Videos - Whilst we watch the sordid, peeping-tom nature of a character in the film, it is accompanied by the innocence of this track. It changes you feeling about what you are watching and distorts your perception. This is a perfect example as to how the soundtrack truly changes a film completely.
19. Still Dead - Almost a 'remix' of Dead Already but with much more percussion. A great example of the almost tribal soundtrack Nedwman creates.