StockStat is the most comprehensive stock website that I have seen on the internet, and it is also free! You will see news on hot stocks, X-dividend days, and much more. The website compiles important links about stocks where they are discussed on other websites as well as showing the current chart and news about whatever stock you wish to research.
Another great feature of StockStat is that you can set up your own stock portfolio there, and you will have immediate access to all the important information about your stocks. For example, if Apple is one of your favorite stocks, you can see the chart, news, statistics, and other links about Apple all on one page. In other words, your Apple page at StockStat will give you links at the bottom of the page to SeekingAlpha, Zacks, Google, Yahoo Finance and other places where you can perform due diligence about AAPL. I don't know of any other website which gives you as much information as StockStat about specific stocks.