It can be a single or a soundtrack. I'd have to say my favorite single is Together 2007. I loved that opening (in fact it is my ringtone) as well as Oracion. As for soundtracks, I would have to say the Jirachi one is my favorite. I think the tracks for the short really stand out in comparison with the tracks for shorts from other movies, and I felt the music really conveyed a sense of the sadness Max faces when leaving Jirachi. One of my favorite tracks was the Butler's Theme. It was really dark-sounding but really cool at the same time. And to top it off I really enjoyed the ending theme as well.