Life is a game (at list this american capitolist life that I am living is). Given that premise, i've been analysing some of the key playing peices, credit/debit cards.

Discover: my first choice, the reason being the obvious cash back. Takes a small dent out of sales tax.
American Express: of dubious value at this point, given Discover's quality customer service, but still have never failed to settle a dispute. Most useful for purchasing plane tickets for their travel insurance and if the airline folds you can get your money back. So far have more than made up the annual fee in purchase refunds.
Visa/Mastercard: necessary as backup only. Good to find one with some side benifit. AT&T Universal Card often offers 0% interest for a while, or LLBean card for free shipping.
Debit Cards: avoid actually using since the money comes out directly breaking the monthly cycle of tracking finances, but useful to have the after hours access to the checking/savings account.