Most businesses in the U.S. as well as thousands around the world choose a domain name ending in ".com". Some businesses outside the US also choose to end the name in a country code, such as ".com.au" (Australia). Unless your customers are mainly based within your country and you want to make a point of being a local business, then it is best to just use ".com". Many businesses outside of the US use a country code preceded by ".co" for commercial, such as "yourdomain.co.uk".