Oprah Winfrey is one of the richest women in America. The talk show queen - who made $100 million last year - is now worth $1.4 billion. However, Oprah only comes 562nd on the Forbes magazine rich list. Fellow media mogul, Martha Stewart's personal fortune fell from $1 billion to just $500,000. As a result the domestic-goddess-turned-TV-host dropped off the list just one year after qualifying.

Elsewhere, Microsoft founder Bill Gates held on to his position as the world's wealthiest man for the 12th year running - his net worth rose from $46.5 billion last year to an all-time high of $50 billion. 'Star Wars' creator George Lucas also made the cut ($3.5 billion), as did DreamWorks heads Steven Spielberg ($2.8 billion) and David Geffen ($4.4 billion). Their business partner, Jeffrey Katzenberg, fell off the list.

Tycoon-turned-TV-presenter Donald Trump held his place on the list with the fortune remaining unchanged from last year ($2.6 billion). However, he admits making a billion dollars doesn't mean as much these days. He revealed: "There are more ways to do it. I think its easier now than ever before.

Forbes' associate editor Luisa Kroll agrees, saying: "Making a billion just isn't what it used to be."