It may not be as obvious as you think:
http://network.nature.com/people/charlesdarwin/blog/2008/12/20/my-first-port-of-call-for-scientific-news
I get all of mine from science blogs, scientific journals, and my adviser.
I don't even pay attention to the news anymore unless its posted about on PD or talked about on the Daily Show or Colbert Report.
ArXiv.org
Also ars, /., etc.