Music from the 500 Days of Summer trailer
If you don’t know which songs are playing in the 500 Days trailer, they are, in order of appearance,
There Is a Light That Never Goes Out by The Smiths,
Us by Regina Spektor,
Black Tambourine by Beck,
You Make My Dreams by Hall & Oates,
and Vagabond by Wolfmother.
Check out the whole 500 Days of Summer soundtrack.
edit: Thanks to Sarah for her correction.