What's important to make good coffee?
Here are some of the things that make a difference, in order of impact:
1. Water. Coffee is mostly water, so if you have bad water, you will have bad coffee. Distilled water leaves the coffee flat, so I use spring water. You can buy it by the gallon pretty cheap.
2. Fresh Ground. If you buy coffee that has been ground already, then much of the flavor is gone already too. Even grinding the night before can let a lot of the flavor evaporate before you get to put it in your cup.
3. Fresh Roasted. After a couple of weeks, the flavor starts to diminish, so even bean coffee at the grocery store has lost a lot of it's flavor already. This is one key reason that home roasting is important, you can roast only as much as you are going to brew each week.
4. Good Beans. This is where taste comes most into play. I like a good, bright Kenyan coffee, but YMMV.
5. Roast. From "city" to "French", some people like darker roasts, but if you have good beans, I think it's best to stay away from the really dark (burnt) roasts. Different beans are better at different roasts, and home roasting gives you the opportunity to make it exactly the way you like it.
6. Brew Method. Any method except a percolator will give you good results if you do it right. I continue to experiment with different drip-brewers, and presses with various results.
There are other factors, and I'm sure there are people who disagree which ones are more important, but if you get these ones right, you will enjoy really good coffee!