Crispin Porter & Bogusky began the decade with just over 100 staffers and a reputation as a strong regional shop that had done award-winning anti-smoking work. The MDC Partners agency will enter 2010 with more than 900 staffers, a client list including marketers such as Burger King, Microsoft, Domino's and The Gap, and its portfolio stuffed with the some of the most memorable marketing campaigns of the century thus far. Having successfully moved its center of gravity from southern Florida to Boulder, Colo., creative legends Alex Bogusky and Chuck Porter have gone international in their own distinctive way: by buying the Swedish digital shop Daddy and rebranding it CPB Europe.

In 10 years, R/GA has shrugged off its film- and print-production roots to become the premier digital agency, a dominance exemplified by Nike Plus, which introduced the idea of platform-based, utility-driven marketing to many. The platform allows runners to log running data by syncing Nike footwear with iPods, and, years later, it still stands out as a prime example of how marketing content can create consumer value. Under Chairman-CEO and Chief Creative Bob Greenberg, the Interpublic agency's client list has included heavyweights such as Nokia, Verizon and IBM, and most recently, Walmart and MasterCard. Today, it counts more than 600 employees worldwide, with offices in London and San Francisco, and has plans to grow its global footprint. R/GA is already showing signs of its next evolution into a full-service agency with digital at its core: It recently won full creative agency-of-record duties for Ameriprise Financial.

The marriage of scale and creativity in advertising is usually not a long one, but TBWA has demonstrated that being a global network doesn't mean the bean counters have to take over. Under the leadership of Jean-Marie Dru, CEO Tom Carroll and creative icon Lee Clow, TBWA grew into a thriving global player this decade, combining the creative chops of a lean micro-network with a much bigger footprint. Standout work for Pedigree, Mars and, of course, Apple, whose "Get a Mac" campaign could rightly be called the campaign of the decade and remains a testament to the power of a well-executed creative idea.

Mother pioneered the agency-as-brand approach, dealing fearlessly with clients and putting creativity and playfulness center-stage. The independent agency employs 400 people across three continents, and it's spawned 20 new companies, including Naked -- now a global player in its own right -- as well as Mother, New York; Madre, Buenos Aires; digital agency Poke; and design agency Saturday. The agency established an advertising-as-entertainment approach that has been widely imitated, and much of its work is now a mainstay of British culture. Its Coca-Cola "I wish" commercial was the first non-U.S. spot for the main Coke brand to run in the U.S.

AKQA has managed to grow into one of the top global digital agencies while keeping its creative prowess and independence. Not bad for a shop whose operations were confined to the U.K. at the decade's start. In 2001, consultancy Accenture invested in the company to bring now-CEO Tom Bedecarre's agency, as well as web developer Magnet Interactive and Singapore-based The AdInc into the family to establish the brand's global footprint in Europe, Asia and the U.S. Since then, the network has survived the dot-com bust and built itself up again to 750 people in six offices. Its roster has included Nike, McDonald's, BMW and Visa. AKQA has also made its mark by designing non-ad brand platforms for Microsoft (the user interface for Xbox 360) and Fiat's recent EcoDrive application that mines data and stores it on USB keys in cars.

Goodby, Silverstein & Partners, like Crispin Porter & Bogusky, is an illustration of what happens when an agency forsakes silos and its ego to simply focus on the work. Located only in San Francisco, Goodby combines new-business performance, creativity and business smarts to remain on the short-list of top shops in the land, with a client list that includes Sprint, Frito-Lay, HP, Yahoo and Haagen-Dazs. In 2007, it won Ad Age's Agency of the Year after demonstrating some strong digital work. Since then, it's continued to show that a one-stop-shop for creative solutions is the model for an advertising agency in our day and age.

Without holding-company backing, independent PR shop Edelman has not only come through two significant recessions this decade, but it has also managed to solidify itself as the leading agency and most recognizable name in the entire industry. Whether it's through the use of traditional PR tactics or the development and implementation of digital, blogger and social-media programs, the agency continually breaks new ground in the world of communications and has redefined the role PR agencies are playing in the marketing mix. Led by the PR industry's most influential voice, CEO Richard Edelman, the agency, whose client list includes some of the biggest brands in the world, such as Walmart, Starbucks, Burger King, Microsoft and Pfizer, will rack up nearly half a billion in worldwide revenue in 2009. The only major hiccup these past ten years was the Wal-Mart Across America blog snafu back in 2006.

Not many agencies come out the other side of mergers with their health intact. Fewer still make the whole bigger than the sum of their parts. But Weber Shandwick, not even a full decade since it was incorporated in 2001 after a series of mergers between three shops, has successfully pulled off the complicated act of a major agency merger. Described by many as the most professional agency in the sector, the Interpublic Group of Cos. shop is the largest PR firm in the world, with offices in more than 70 markets globally. And its client list is a who's who of blue chip marketers including General Electric, Unilever, Johnson & Johnson, MasterCard, Microsoft and Verizon.

Bartle Bogle Hegarty was 18 years old in 2000, and had just sold a minority stake to Leo Burnett, the first deal of its kind. In the decade since, BBH London, Singapore and New York were joined by BBH Sao Paulo, Shanghai and Mumbai, securing the agency's place in history as the model of the tightly branded yet truly global micro-network. In the past 10 years, BBH won -- and kept -- some of its biggest clients, including KFC, Barclays, Vodafone, Omo, British Airways and LG, while retaining two founding client Levi's and Audi. Often a step ahead of the rest of the industry, BBH launched the first music publishing company in advertising, a content department, and created an engagement-planning function and brand-invention arm Zag.

This decade has been brutal on Madison Avenue's giants, now faced with a stark reality: Modernize or die. It's a nearly impossible task, but Omnicom Group's BBDO has made a go of it. In the capable hands of worldwide CEO Andrew Robertson, BBDO managed to become a new-business machine in the middle part of the decade. It netted Agency of the Year honors in 2005. And, despite once being known primarily as a factory for TV spots, BBDO has managed to display some digital acumen on work for M&M's and HBO. Massive challenges loom during the new decade: BBDO and parent Omnicom need to recover quickly from the crumbling of their relationship with Chrylser, not long ago its largest client.