For investors, there’s nothing better than cold, hard cash. Companies that generate mounds of cash flow not only have more than enough money to invest in growth-focused initiatives, but they can also reward investors through share buybacks and dividends. Three such cash-flow machines are Gilead Sciences (NASDAQ: GILD), Cisco Systems (NASDAQ: CSCO), and Kinder Morgan (NYSE: KMI). Our Fool contributors weigh in on all three.