A great everyday card for me (and I assume for many Mustachians) is the Sallie Mae Mastercard. Sign up bonus of $25 for just using it in first 90 days, nothing to write home about. But what it does offer is:
5% back on first $250 in groceries every month
5% back on first $250 in gas every month
5% back on first $750 in bookstores every month (Amazon is apparently coded as a bookstore. I'm not sure if merchants on Amazon are coded this way, but if not, you could probably buy an Amazon gift card to get 5%, and then apply the gift card to an Amazon merchant purchase. I just got approved for this credit card so I haven't figured this out yet but I eagerly await my new CC =) )
1% on everything else
Rewards can be redeemed as a statement credit or towards your Sallie Mae student loan balance, if you have one.
A great card for those of you who like to travel and have sufficiently high net worth is the Bank of America Travel Rewards card. I have no personal experience with this card, but I've read about it from other places. It functions like Barclay's travel rewards card ( I forget the exact name) where if you make a purchase with a merchant whose merchant code fits a travel category, as determined by BoA, you can apply your points to the travel purchase as a statement credit. Apparently their definition of travel is pretty broad - I believe it includes airfare, hotels, resorts, cruises, rental cars, and some others.
No annual fee
Baseline reward is 1.5 points per dollar spent.
If you reserve travel through their portal, you get 3 points per dollar spent (except the extra 1.5 points per dollar spent on airfare is capped on the first $6000/yr)
When redeemed against travel expenses, the value of a point is 1 cent. If redeemed as strictly cash, the value of a point is 0.6 cents.
Now why did I say for those who have sufficiently high net worth? Well, if you have at least $20k, $50k, or $100k combined with BoA or Merrill Edge (this part is critical, since it will let you keep that large amount of money invested), then you can get a bonus on your rewards of 25%, 50%, or 75% by enrolling in the Preferred Rewards program (apparently you will need to have an average balance at the thresholds for at least three months before you can enroll). So, your maximum baseline reward now becomes 2.625 points per dollar spent. And if you book through their travel portal, you get 5.25 points per dollar spent. And as long as you always redeem against travel expenses, you've now used your Mustachian habits of saving money to create a 2.625% cash back on everything card, and 5.25% cash back on travel booked through BoA's portal.
Incidentally, these 25%, 50%, and 75% bonuses can also apply to the BoA 3-2-1 cash rewards card (gas, groceries, everything else) to get up to 5.25% on gas, 3.5% on groceries, and 1.75% everything else.