G. Google
The epitome of internet success stories, Google began life as a search engine, and has grown, as youre certainly aware, to offer a service portfolio incorporating everything from an email client (Gmail) and web browser (Chrome) to the Android operating system. Honourable mentions go to Groupon, the daily deals site offering discounts for users at local businesses, though recent news indicates the model to be struggling, and GameFAQs, a comprehensive gaming site that focuses primarily on user submitted content.
H. Howstuffworks
One of the many benefits of the web is its ability to answer almost any question imaginable, and such a concept drives Howstuffworks, a site offering assistance and guidance on a wide array of topics in a superior manner to its competitor, eHow. An honourable mention goes to the Huffington Post, one of the webs most popular destinations for news and opinion.