Quick Photoshop Layer Shortcut

Here's a very useful Photoshop keyboard shortcut to create a copy of merged layers while leaving the original layers intact. 

On a the PC the shortcut is:

CTRL + ALT + SHIFT + E

Photoshop will merge all of the layers into one new layer and insert it at the top of your layers stack. It leaves all the original layers unaltered so you can still go back to them if you need.

Kelby Training's Matt Kloskowski provides a quick video tutorial/demo here.