The ideal water temperature for a great cup of coffee ranges from 195 - 205 degrees Fahrenheit.
This chart outlines the boiling temperature of water at different elevations. As you can see, if you live above 4000 feet, you can boil your water.
Use fresh, clean water to brew the best cup. If you're lucky, you can use water straight from the tap. In areas with high levels of minerals, invest in a water filter. It will reduce the number of particulates in the water to a more optimal level.
Avoid using distilled water. For the best coffee flavor, a small quantity of particulates need to be present. Distilled water will make your coffee come out tasting flat.