Control arrow key to jump to the next word
To disable the shortcut for switching to spaces go to the keyboard shortcuts tab of the keyboard preferences pane. Select Mission Control on the left and then un-check the 'Move left/right a space' options.
It seems like OS X automatically re-assigns ⌥→ and ⌥← to jump one word forward/backward, as soon as you disable the 'switching space' shortcuts in the Mission Control.
System Preferences → Keyboard → Shortcuts and uncheck the Mission Control shortcuts
To move from word to word, you must use Option + arrow keys