composite, s-video, component - since your display is digital you're not going to notice much of a different at all between those 3 no matter how expensive your cable is.  Getting a digital video connection to your LCD is the key - which means either DVI-D or HDMI, neither of which your cable box has.  Get a new cable box.
	
		
			
		
		
	
				
			 
	 
 
		