Here is my list of the top 5 Google products that I use all the time.
Provides high quality stats about website traffic. Absolutely amazing, and 100% free.
Google advertising and it is enornmous. The program alone brought Google over $21 billion in revenue in 2008, Google main source of revenue. And it is only growing.
Awesome service by Google for managing buying/selling products online. Has small transaction fees, similar to Paypal.
Google email – big, fast, efficient, easy, and free!
Find where you need to go; anywhere in the world. Street view is just icing on the cake, it is absolutely amazing.
I know this is six, but I had to add this in. Ad manager is a free utility to manage advertisements on your webpage. They not only provide this service to you, they also provide amazing reports to help you get the most out of your websites.