Boasting its "biggest year in Xbox history," Microsoft today sent word that life-to-date unit sales of its Xbox 360 console are now up to 28 million worldwide, which the company says puts its lead over rival PlayStation 3 at more than eight million units. The company's leading Xbox Live service also saw plenty of growth last year, as membership swelled to 17 million and online spending increased by 84 percent. In fact, digital downloads and Xbox Live revenue in general grew to more than $1 billion since the 360 launched three years ago.

The 2008 Holiday period in particular was a highlight for Xbox Live, as it saw its "busiest week ever" between Christmas and New Year's Day. Microsoft said there were more than 1.5 million concurrent members online.

"For Xbox, 2008 will be remembered around the world as a pivotal growth year at retail and online — even in the face of tough economic conditions," said Don Mattrick, senior vice president of the Interactive Entertainment Business at Microsoft. "Worldwide, a record number of players flocked to our broadest games and entertainment lineup ever, while the New Xbox Experience thrilled millions of fans by making our console even more engaging. And yet, we've only provided a glimpse into the new world of interactive entertainment that we're imagining. The best of Xbox 360 is yet to come."