Always use Barrage in conjunction with Empyreal Arrow, if you play your cards right you should be able to fit about 6 Empyreal Arrows between Barrage CD's, (that's assuming you use EA as soon as it comes off CD) if for whatever reason you can't use Empyreal Arrow or it's on CD and you REALLY need something dead RIGHT NOW then I'd recommend you pair it with Heavy Shot.
Though for general use, definitely Empyreal Arrow
