3x ATR is good if its like your first week trading.
as mandlebroset said, 6x is good once you're past novice level.
i have a blackbox system running on ES, NQ and 6B that pulls 27x, 25x, and 15x ATR, respectively). Unfortunatley im only able to trade 50 ES cars at a time which limits my daily P/L (after commissions) to around $75k. Everything is automated so i just sit back and watch my account grow while i drink $20k wine and read Trader's Monthly. Sometimes tho when the weather is nice i'll go out and polish my Veyron instead.