Help! Need advice on best business credit card to use for expenses to rack up rewards

I am the partner in an ecommerce startup where we are purchasing thousands of dollars of inventory every day by credit card. (well into 7 figures by the end of the year)

The main reason we are electing to use credit card is because it is a great opportunity to rack up tons of rewards points (our suppliers even recommended this). Anyone have any experience as far as the best one to go with or the best way to negotiate for this?

We aren't really looking to hold a balance, typically a days purchases will be paid back within 5 days. We were originally thinking of an AMEX Business Gold (http://www.credit-cards-with-rewards.com/American_Express_Business_Credit_Card.htm) but unfortunately most of our suppliers limit us to Visa or MasterCard.

I'm currently leaning towards a Capital One No Hassle Miles Rewards Card http://www.credit-cards-with-rewards.com/Capital_One_Credit_Cards.htm 1.25 x dollar and they offered a pretty high credit limit.

I'm still in the beginning stages of researching this and have been spinning my wheels a bit so any advice would be appreciated!