Ever just want to fill a selection or layer with the background or foreground color in Photoshop? Forget heading all the way over to the palette to choose the Paintbucket tool – just press Command (Apple key)+Delete for the foreground color, or Option+Delete for the background color (Alt+Backspace and Control+Backspace on Windows).
And for a bonus tip (and one I often forget): Hold down the Shift key with either of the shortcuts, and the Fill will preserve transparency. This will result in only filling in color where there are actual pixels present in the layer, effectively tinting the pixels only in that layer with whatever the foreground or background color is. Cool!
And of course, you already know you can swap foreground & background colors using the X key, and can reset the foreground/background colors to the default (black/white) by pressing the D key.