There is no actual difference between "espresso beans" and "coffee beans"; in reality, they are both just "coffee beans". When you see something packaged as "espresso beans" or "espresso roast" it is most likely just a dark roast designed to taste good when ground ultra fine and used to make espresso.
When it comes down to it, the only thing that changes is the grind (espresso is generally ground very fine). The actual roast or bean used is up to your personal preference; one local coffee shop that I enjoy uses a blonde roast for their espresso, while another one right down the street uses a very dark french-italian roast.
As far as the beans themselves are concerned, there are only two types of coffee bean: C. arabica, and C. robusta. Both are suitable for espresso, or drip coffee, or any other preparation method (in fact, you've probably had both many times without even realizing it).
TL;DR — There is no such thing as an "espresso bean"; it's all just coffee.