A list of some of the most common & useful Photoshop keyboard shortcuts. Getting to know them is a worthwhile investment and saves a ton of time over the long haul.
PC users, replace Opt with Alt, and replace Cmd with Ctrl.
Tools
Move Tool
VMarquee Tool
MLasso Tool
LMagic Wand Tool
WCrop Tool
CEyedropper Tool
IHealing Brush Tool
JBrush Tool
BClone Stamp Tool
IHistory Brush Tool
YEraser Tool
EGradient Tool
GDodge Tool
OPen Tool
PType Tool
TPath Selection Tool
AShape Tool
UHand Tool
HZoom Tool
ZDefault Colors
DFlip Colors
XQuick Mask
QFull Screen
FRotate View
RHide Panels + Tools
TabDecrease Brush Size
[Increase Brush Size
]Workflow
Group Layers
Cmd (Ctrl)+
G
Image Size
Opt (Alt)+
Cmd (Ctrl)
+
I
New Layer
Shift+
Cmd (Ctrl)
+
N
Save For Web
Shift+
Opt (Alt)
+
Cmd (Ctrl)
+
S
Fill with Background
Opt (Alt)+
Delete
Fill with Foreground
Cmd (Ctrl)+
Delete
Inverse Colors
Cmd (Ctrl)+
I
Inverse Selection
Shift+
Cmd (Ctrl)
+
I
Deselect
Cmd (Ctrl)+
D
Duplicate Layer
Cmd (Ctrl)+
J
Free Transform
Cmd (Ctrl)+
T
Hide Selection
Cmd (Ctrl)+
H
Stamp Visible
Shift+
Opt (Alt)
+
Cmd (Ctrl)
+
E
Merge Visible Layers
Shift+
Cmd (Ctrl)
+
E
Stamp Down Selected Layers
Opt (Alt)+
Cmd (Ctrl)
+
E