Bloomberg - the standard for getting caught up on the day's developments in financial markets. Well worth the subscription.
The Wall Street Journal - another great source on news in financial markets. typically longer form articles.
Stock Market & Finance News - Wall Street Journal
Seeking Alpha - Security specific research and other market news
Seeking Alpha | Stock Market Analysis & Tools for Investors
Finviz - Awesome tool to get an overview of the markets (look for the grid of stocks on the right)
Atom Finance - aggregated financials (income statements, balance sheets) on every public company. Also includes the ability to build financial models of companies with the given data.
Modern investing tools and data for everyone.
Yahoo Finance - news and financials in one place. good for getting a quick overview of a company.
Yahoo Finance - Stock Market Live, Quotes, Business & Finance News
Investopedia - This is the finance encyclopedia
Learn more about a few niche topics in finance
Bill Ackman - Everything you need to know about finance and investing