If you're considering personal cards, USAA has 2.5% cash back on everything if you have a bank account + $1000/month direct deposit with them. http://usaa.com/limitless (limited to certain states)
Active, retired and honorably separated officers and enlisted personnel of the U.S. military.
Officer candidates in commissioning programs (Academy, ROTC, OCS/OTS).
Adult children of USAA members who have or had a USAA auto or property insurance policy.1
Widows and widowers of USAA members who have or had a USAA auto or property insurance policy.