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I find the layout uneven, I think it's mainly because you're three main sections have no real borders - I'd try framing your sections to make it look more solid. Look at using faux columns.
the left navigation is too far left, the gutter between the left nav and the content is far greater than than the content and the right sidebar.
But i'm looking at it 1440px wide - Keep the gutters consistent in larger windows.
The text-indent on the main content section is a little off-putting.
The zig zag in your header doesn't look professional and leaves the page unbalanced.
You're footer needs some more love too, think of framing it and laying it out relative to the other elements on screen as it looks 'left to the side'.