The American Express Business Rewards Gold card is, for a limited time, offering a 50,000 Point bonus when you spend $5,000 in 3 months (application here). The card offers 3X points on airfare, and 2X points on gas, advertising and shipping.
Amex has done a few one-day offers of 75,000 points for the same card, so unless you need 50k Membership Rewards points quickly (tho it won’t be THAT quick), I’d wait til that offer comes back.
The first year is free, and it’s $175 thereafter.
As an everyday business card, I prefer the Ink Bold® Charge Card® Charge Card, as it has a lower annual fee ($95 after the first year), 5X Ultimate Rewards points on office supplies, phone, cable & Internet and 2X on gas & hotel. Plus, as a United guy, I like that the Ultimate Rewards points can be transferred into that program. I’ll keep the card even after the annual fee is due because the 5X bonus on cable/phone/internet alone will make it worth it for me.