Declaring Vars...

// Which is "better"

// This:
private var moveHorizontal : float;
private var moveVertical : float;

function Update () {
	moveHorizontal = Input.GetAxis ("Horizontal");
	moveVertical = Input.GetAxis ("Vertical");
	movement = Vector3 (moveHorizontal, 0.0f, moveVertical);
	transform.Translate (movement, Space.World);
}
// Or This:

function Update () {
	var moveHorizontal = Input.GetAxis ("Horizontal");
	var moveVertical = Input.GetAxis ("Vertical");
	movement = Vector3 (moveHorizontal, 0.0f, moveVertical);
	transform.Translate (movement, Space.World);
}