You can use any type of whole bean coffee, with the exception of caramelized beans.
Different roasts will offer you a different taste (and aftertaste).

Roasts vary from light (with a lighter, sharper flavor) to dark (very deep, rich flavor).

An example of different types of roasts are:
Light Commercial Roast (Light Brown) – Non-oily, light in color, mild taste
Medium Roast (Cinnamon Brown) – Stronger flavor, non-oily, preferred in the USA
Medium-Dark Roast (Brown, some oils) – Rich in color, some oil, bittersweet aftertaste
Espresso- Dark Roast (Dark Brown, oily) - Shiny black, oily surface and evident bitterness