Here are 3 of the “12 Best LinkedIn Company Pages of 2012”:

Adobe : Focus on the product. The computer software giant uses the "Products and Services" section of its Company Page to showcase its products, tools and services in a compelling way, LinkedIn senior product marketing manager Lana Khavinson says. Filling out the products section is important because individuals can recommend and share each product which, in turn, helps engage customers.
Since the first product that's featured in the Products and Services area appears prominently in the right rail of a Company Page, Khavinson recommends choosing the one that you want to highlight the most for that spot.

CNBC : Killer status updates. As a media outlet, CNBC provides relevant and timely status updates, which Khavinson says engage followers in a dialogue about the headlines of the day. CNBC reaches LinkedIn's professional audience by tailoring relevant information in their efforts to build relationships, she says.
The key to driving the highest engagement for your own status updates is by sharing links to interesting content and then soliciting feedback on the content that was shared, Khavinson says. For example, publish a link to a story or post and ask a question regarding the content you shared.

Walt Disney : A dynamic careers section. Disney communicates new job openings as they become available through status updates, and uses eye-catching imagery and video to capture users' attention. It "showcases the magical lives of Disney employees while highlighting a variety of career opportunities available," Khavinson says.