The Discover® It for Business card provides a great rewards based business credit card for small businesses.
This credit card provides a very competitive cash back rewards system up to $2,000 each year, providing 5% cash back on office supplies and 2% on gas. It's really geared towards those who are going to be using the credit card for domestic office expenses, and who plan on those expenses being $40,000 or less annually. If that's the case, this card is a no-brainer in saving 5% on all of your office purchases.
It is worth noting, however, if you're going to be using your credit card extensively for Travel, there are significantly better options for businesses - like the Spark Miles for Business Credit Card . But for other small businesses, this is a highly competitive card.