Nice I like the colouring.
As far as hierarchy goes I feel that it's the repeated sloped hill icon on the news/login etc that distracts me. I like the way it looks but it just appears far too many times in too small a space for me. Maybe you could just use it at the top of each column and use type differences to distiguish each section? Though it may all feel better if there is more content on the page and the repeated icon image isn't so close.
Not sure what the background colour on looks like on a PC but on my mac it's incredibly pale - as good as white didn't even notice it a first, maybe make this a little stronger to help the seperation, or you could reverse the whole columns out of the green instead ?
Overall feel I like - time for a bit of a tweek
