Fidelity 2% Amex for low spending.
Amex Blue Cash for high spending.
Citi Forward for restaurants, books, entertainment (>3.5% cash back)
PenFed Cash Back Visa for gas and groceries (5% and 2%, respectively, credited at the end of each month)
Fidelity Amex for everything else (2% on everything)
(Optional) Chase Freedom (5% on quarterly bonus categories)
I guess it's my Costco Amex. I mostly buy my gas there, so the 3% come in handy, and restaurants (another 3% category) are my major vice.
I'm going to go with the Discover More as well.
Backups would be split between Nationwide for low rate and AMEX Green for controlling my spending
I would have to say my BOA World Points. They gave me my first visa card. Its my highest limit ($1000). I love my CareCredit (4000) but I can't take that to the grocery store...lol