Julieanne Kost's Blog

PSCS5 – Simply select multiple layers in the Layers panel and use the Opacity and/or Fill slider to change the Opacity/Fill of all selected layers at once.

Option-Delete (Mac) / Alt-Backspace (Win) + Shift will fill with the currently selected history state and preserve transparency (so that only those pixels that have information in them are filled).

Option-Delete (Mac) / Alt-Backspace (Win) + Shift will fill with the foreground color and temporarily turn on the Lock Transparency option (so that only those pixels that have information in them are filled).

Option-Command-Delete (Mac) / Alt-Control-Backspace (Win) fills with the currently selected history state.

Shift + Delete (Mac) / Backspace (Win) brings up the fill dialog box as does Shift + F5 (function key).

Option-Delete (Mac) / Alt-Backspace (Win) fills with the foreground color.
Command-Delete (Mac) /Control-Backspace (Win) fills with the background color.
Of course these shortcuts work with all sorts of layers including Type and Shape layers.