The best all around cards are
MBNA Smart Cash Master card 0 Fee, 3% rebate for grocery and gas(up to 600 per month). 1% for other expenses.
Costco True Earning AMEX card: 0 Fee, 3% rebate for restaurants where AMEX is accept (McDonald, KFC, etc)
CapitalOne World Master Card: 120$ fee, (rebate for 100$ worth of points). 2% rebate for all expenses. Sign up bonus $350 worth of points). Points can use for travel (full value), or cash rebate(1.5%) or other merchandise which I don't think worth it.
So if you use MBNA card for grocery and gas.
AMEX for costco and restaurant and CapitalOne for rest of expense, you will get quite a bit of rebate each year/month.