I liked the Google Earth tool. It would be good way for students in my international business classes to study terrain and imagery of different countries that they might consider "starting" a business in. The 3D tours of buildings allows them a way to see places they might not ever get a chance to. (Granted, that might be more from history class viewpoint, but it would be good way to create bridge between history and business classes).
A tool more relevant to business classes would be Google Finance. (http://www.google.com/finance). Students can use this when studying stock market, and begin to see how an event that occurs in the world (such as OPEC changing price of barrel of oil) can cause changes in marketplace in other countries, and then affect world economy, etc. (for instance, one of the articles on their today talks about how mortgage fraud is on the rise; students would be able to study how that might affect them if they were to be looking for mortage to buy a house).
From stock market standpoint, I liked how it has a table on current trends; students can follow popular stocks, or see which stocks were the biggest gainers/losers for that given day, etc. It also has a chart where it breaks different sectors down, so they can see how, say, the energy industry stocks are doing compared to transportation, or utilities, etc.