Best Cashback Cards:

Personal:
Costco Amex Cashback (3% Dining, 2% Travel, 1% Etc) No Annual Cap
These pay 5% Cashback at Grocery Stores, Gas Stations, and Drugstores and everything else is 1%:
Chase Cashback 5% (Great if you can get the $50 signup) $300 Annual Cap
Citibank Dividend Platinum MC 5% Cashback $300 Annual Cap

Small Business (Don't report debt on your personal credit report!):
Advanta Platinum MC 5% Cashback $300 Annual Cap, Primary Rental Ins
Costco Amex Business Cashback (3% Dining, 2% Travel, 1% Etc) No Annual Cap.

Because of tiered cashback rates, only high card spenders (over $6500 annually) should consider Amex Blue Cashback.

All have no annual fees. Advanta has a fixed rate 7.99% Purchases with 0% for 1 yr on Balance Transfers. Advanta is my favorite.

Watch out for cards that say "Up to" a certain percentage as these are usually tiered cashback rates like Discover or many others. Must spend a very large amount yearly (perhaps a business) to make it worth anything.

ILUVCITIBANK wrote in another thread about cashback that I find to be very true and worth repeating:

"Comments ? My sense is as traditional affinity programs get diluted (capital One's), devalued (AA and milesaver) and neutered (AMEX Centurion and Membership Rewards in general), its time to abandon ship on pure point and mile collecting and seriously consider CASH BACK strategies. Then take the cash and using priceline.com, kayak.com, and orbitze.com- style site maximize your leverage on the SPEND side. These affinity programs are really in "take back" mode as their respective economies (hotels, airlines) strengthen, so the value proposition or points and miles is diminishing."

It appears cashback may be a better way to go. Checkout cashback strategies at http://www.fatwallet.com/t/52/564358