Hard to go past Harvard Business Review for quality articles and discussion hbr.org
For business news I do like bloomberg.com and businessspectator.com.au for an Australian feel.
Whilst distinctly US the New York Times – via app for iphone/ipod touch/ipad is good
For books – amazon.com or bookdepository.co.uk works for me
http://behaviouralinvesting.blogspot.com/ for James Montier on Behavioural Investing
Blogs I like:
For social media
I have grown to like twitter.com as a means of linking to articles I like when surfing the net. LinkedIn.com is the business worlds facebook (facebook.com) which is good for social information.