MBNA credit card offer 2% cash back
For gas, drugstore, and supermarkets, there are Chase and Citi bank credit card that offer 5%.
For others, MBNA credit card has been the highest so far. I just opened three weeks ago.
The catch, you have to open a 529 plan with fidelity. (either minimum to open is $1000, or automatic investment $50/mon to avoid the $30 annual fees)
I read the blog from Jonathan, who wrote the pros and cons of the MBNA credit card.
http://www.mymoneyblog.com
This is the website that offer the credit card.
MBNA 2% Credit Card