What's the best browser for the enterprise?

In a recent article at eWeek, they look at how Internet Explorer is one of the most widely used browsers in the enterprise, but may not be the best for the industry. They state that IE6 and IE7 are loosing market share quickly, but IE8 and Firefox 3 are gaining share quickly. He also points out that Firefox now controls 27.73%of the market, and Google, Opera and Apple all have single digit market share. So if IE is not the best for the enterprise, why does it have such a corner on the market? The article looks to suggest that since it is a standard feature on all new PCs, many companies see it as a quick and easy way for their employees to surf the web. What do you think? What is the best browser for the enterprise, and will IE loose its share anytime soon?