If you are looking for attractive income stocks, here are two energy giants you'll want to buy and one to be leery of.The energy sector is known for being volatile, given that oil and natural gas are commodities. But there's one niche in the energy sector that tends to be far less volatile -- the midstream. Yet all midstream companies are not created equal.If you are looking for an ultra-high-yield investment, consider midstream giants Enterprise Products Partners (EPD 0.03%) and Enbridge (ENB 0.61%). Meanw ...