It looks pretty nice. A couple of things though:
– The serif font for the logo isn’t great
– Hovering a nav item make it shiver on Chrome Canary; kind of annoying
– I feel like dropdowns could be improved
– I don’t really understand where the content is supposed to be since there is a huge header image
Just personal opinion of course but I actually love the rich image, :hover transitions on parent `nav` items and the semi-translucent header (although I would second @HugoGiraudel‘s comment about the negative impact of this on the readability of the submenus – perhaps this could be tackled by simply choosing a colour, like black instead of white, that might work better in that particular circumstance).
I second @paulie_d ‘s suggestion for using inline-block on the nav. Looks to be a great start, the only other minor complaint I have about it would be the comment focus event. It’s just incredibly jarring to have that block pop out of nowhere. I’d opt for a more subtle fade / tooltipy sort of thing.