Editor’s Note: Photoshop CC (2015) recently released. For complete details, see this Photoshop CC (2015) FAQ.
Photoshop CC 2015 now allows you to add multiple of the same layer style to a single layer. Add multiple drop shadows, strokes, overlays, and more!
[youtube https://www.youtube.com/watch?v=PYhhAZqBHf4&w=560&h=315]