I think the left-bar should be collapsed by default as most logged in or anonymous user will see the same thing there. Also currently IMO it distracts the main question view. Or at the very least- as you resize the window down, the sidebar should be the first one to collapse. Currently the right hand panel moves to the bottom which is the second most important piece in this page (after the question).
I'm only talking about the question page. Other pages look brilliant with the sidebar. It's just in the question page where this new sidebar hurts my eye.