The initial key mapping:
WASD - Movement
Arrow Keys - Camera
(these two may be switched in the options screen)
Space - Snap camera back to Player
1 through 5 - Combat based Action Commands
Mouse - Move Player, Interact with World Objects, Double-Click to equip/unequip Items, Mouse Over items and abilities for Popup Help.
In-Game keymappings are denoted by parentheses (ie (J)ournal means that J opens the Journal window)