Coffee beans are perhaps the most important part of making coffee. Even if you have the best coffee grinder and espresso machine, bad coffee beans will still make bad coffee. Always use fresh beans, not more than a few weeks old, preferably just a few days old.
There are thousands of coffee beans, and as taste is as subjective as can be, there's no "best coffee bean". However, it is possible to select a number of coffee beans which are generally considered to be the best for a specific purpose, like espresso. If you have a suggestion for a specific coffee bean or list, please let us know.