f1 - Toggles Adobe Online Help
f5 - Toggles Brush style palette
f6 - Toggles Colour, Swatches, Styles palette
f7 - Toggles Layers, Channels, Paths palette
f8 - Toggles Navigator, Info palette
f9 - Toggles Actions, History, Presets palette
Tab (Key) - Toggles all the palettes on screen
Shift + Tab (Key) - Toggles palettes on screen, excluding the Toolbar.

Tool Bar Short Cuts
R (Key) - Blur Tool
E (Key) - Eraser Tool
T (Key) - Horizontal Type Tool
Y (Key) - History Brush Tool
U (Key) - Line Tool
I (Key) - Measure Tool
O (Key) - Sponge Tool
P (Key) - Pen Tool
A (Key) - Direct Select Tool
W (Key) - Magic Wand Tool
S (Key) - Clone Stamp Tool
G (Key) - Gradient Stamp Tool
H (Key) - Hand Tool
J (Key) - Healing Stamp Tool
K (Key) - Slice Stamp Tool
L (Key) - Polygonal Lasso Tool
Z (Key) - Zoom Stamp Tool
C (Key) - Crop Stamp Tool
V (Key) - Move Tool
B (Key) - Brush Tool
N (Key) - Notes Tool
M (Key) - Rectangular Marquee Tool

Out of Ctrl Short Cuts
Ctrl + N - New Document Dialogue Box
Ctrl + M - Curves Dialogue Box
Ctrl + A - Selects all in the currently foreground document or currently selected layer
Ctrl + D - Deselects all in the currently foreground document or currently selected layer
Ctrl + J - Automatically creates a duplicate of the currently selected layer
Ctrl + K - Preferences Dialogue Box
Ctrl + L - Levels Dialogue Box
Ctrl + F4 - Closes current document
Ctrl + ' (Single Quote Key) - Toggles Grid Lines
Ctrl + Q - Quits Photoshop altogether
Ctrl + R - Toggles Rulers
Ctrl + U - Hue/Saturation Dialogue Box
Ctrl + O - Opens New File
Ctrl + P - Print Dialogue Box
Ctrl + Z - Undo last Action
Ctrl + Tab - Toggle between open documents
Ctrl + Shift + C - Copy Merged
Ctrl + C - Copy
Ctrl + H - Toggle Extras
Ctrl + ; - Toggle Guides
Ctrl + Shift + ; - Toggle Snap
Ctrl + X - Cut
Ctrl + Alt + Shift + X - Pattern Maker
Ctrl + V - Paste
Ctrl + Shift + V - Paste into selection
Ctrl + Alt + Shift + V - Paste Outside
Ctrl + T - Transform Tool
Ctrl + Shift + T - Repeats the last performed Transform
Shift + F5 / Shift + Backspace (Key) - Fill Layer Dialogue Box

Combination Number 9 Shortcuts - Ctrl + Shift / Alt
Ctrl + Shift + O - Photoshop's File Browser
Ctrl + Shift + P - Page Setup Dialogue Box
Ctrl + Shift + S - Save As Dialogue Box
Ctrl + Shift + K - Color Setting Preferences Box
Ctrl + Shift + F - Fade Dialogue Box
Ctrl + Shift + X - Liquify Filter Tool
Ctrl + Shift + N - Create New Layer Preferences Box
Ctrl + Shift + M - Launches ImageReady
Ctrl + Shift + E - Merges all layers into a single layer
Ctrl + Alt + Z - Step Backward
Ctrl + Shift + - (Minus Sign Key) - Zoom Out
Ctrl + Shift + + (Plus Sign Key) - Zoom In
Ctrl + Shift + Alt + N - Creates a new empty layer
Ctrl + Shift + Alt + S - Save For The Web Dialogue
Ctrl + Alt (in most Dialogue Boxes) - Changes the 'Cancel' command to 'Reset'
Ctrl + Alt (in the 'Save For Web Dialogue') - Changes the 'Cancel' command to 'Reset' & the 'Done' command to 'Remember'
Ctrl + Alt + ~(Tild Symbol) - Selects the brightest area of the currently selected layer
Ctrl + Shift + I - Inverts a selection
Ctrl + Alt + X - Extract
Shift + -/+ signs(on a layer) - Toggles the different layer modes
Shift + Ctrl + Z - Step Forward