Savoring the pleasure of casually tossing your American Express platinum card on the dinner table? Not so fast. The company has been quietly sending out black "Centurion'' cards to English cardholders with real spending power, and word is they're about to be distributed here too. The ebony status symbols are delivered in velvet cases by security guards. Recipients, who reportedly must have a minimum annual income of $200,000, enjoy "any individual services within legal boundaries," says a spokeswoman, such as secured World Cup tickets or Grand Prix passes and access to private airport lounges. The AmEx spectrum already includes a new blue card, which contains a smart chip and a magnetic stripe to enhance e-commerce security. Now all the company has to worry about is the bruised egos of green- and gold-card holders.