Gates is now one of the world's richest men, proof that being a computer geek can really pay off. In 2008, he stepped down from the daily running of Microsoft to focus on his philanthropic endeavors with wife, Melinda: TheBill & Melinda Gates Foundation works to improve education, fight hunger and develop vaccinations. (Microsoft publishes MSN Money.)

Steve Jobs

Net worth: $5.5 billion

First job: Summer hire at Hewlett-Packard

Steve Jobs was a high school student when he got a summer job at Silicon Valley pioneer Hewlett-Packard (HPQ, news), where he met Apple (AAPL, news) co-founder Steve Wozniak.

Despite Apple's success, the bulk of Jobs' fortune comes from the sale of digital animation company Pixar to Walt Disney (DIS, news) for $7.4 billion.

Giorgio Armani

Net worth: $5.3 billion

First job: Assistant photographer

Giorgio Armani grew up in a middle-class Italian family and had an early fascination for theater and fashion. He got his first job at Milan department store La Rinascente as an assistant photographer and was quickly promoted to the store's style office as a buyer.

Armani has since become the designer and fashion magnate we know today.

George Lucas

Net worth: $3 billion

First job: Teaching assistant

George Lucas made much of his fortune from the iconic "Star Wars" film series.

Lucas' start in film came early but humbly -- he worked as a teaching assistant for Navy students who were studying documentary filmmaking.

Lucas went on to pursue an apprenticeship with Francis Ford Coppola and eventually developed his own name as a Hollywood icon.

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The bottom line

We all know that starting as a newspaper boy or parking lot attendant doesn't promise you'll be a billionaire. What is interesting about the careers of these billionaires is that they discovered their passion at an early age, proving that following your passion can pay, sometimes in the billions.