InformationWeek's annual ranking, now in its 23nd year, spotlights companies across industries using technology ranging from wireless to social media to drive business results.

PACCAR is this year's No. 1 company. In the face of a recession, the heavy truck builder made a bet on in-vehicle electronics that could give drivers and dispatchers more information. The IT organization, led by CIO Kyle Quinn, helped set the vision that top executives at the company embraced. IT pushed ahead despite the downturn and staff cuts, building new startup partnerships to get the wireless and mobile app expertise needed to execute.

The No. 2 company, Levi Strauss, has moved aggressively into social media. Today it has 6.2 million followers on its Facebook page, which gets more than 1 million visits a month. Levi also has created its own global online community for young women, boosting brand awareness and engagement.

No. 3 Waste Management created a price-optimization system that models the factors that drive market prices and price sensitivity in the 25 regions in which the trash-handling and recycling company does business, helping managers decide what price to quote a customer. No. 4 on the list, pharmaceutical services provider Quintiles, has developed cloud computing services that turn IT into a revenue driver for the company. Fifth on this year's list, Catalina Marketing, is on the cutting edge of using big data, real-time analytics.

And that's just the top five. Want more? Here's a look at key insights about the top 10 InformationWeek 500 companies and their tech leaders.

Go to the 2011 InformationWeek 500 homepage