For storage capacity the DVD is best. You can create slide shows and add music plus they can be played on Dvd players connected to a TV.
For just storing photos CDs are OK but for the small cost difference I would go with DVD.
In the end you have to work out which is best for you.
To sum up I would say store the photos on CD. When you want to add the music create a slide show, Then put it on DVD with the music.