I got this photo from flickr, I like how the reflection from the sky is on the water and makes the  background look beautiful.

The Big Picture (Boston Globe -news stories in photos)
Flickr - Photo sharing site (have to be a little more selective with this site)
National Geographic Photo - Nat Geo's photo home - amazing resource
Lens Blog - From the NYTimes - lots of great photojournalism
Lightbox - From the photo editors of Time Magazine
Outside Magazine - Lots of action / adventure photos
vii - Photo agency with amazing work
Magnum Photos - Another agency with award winning work
Scholastic -