I really like the new design, compliments Jin.
At a first look I see only few points of possible improvement, ihmo:
- I don't like too much the drawing image in the header; maybe is just a matter of position, I would try to move it to the side instead of central;
- Search box height is too small
- Font size of related questions (sidebar) is too small
- Probably this morning my brain is still sleeping, but I took more than 20 seconds to see the Ask Question link of new design. Other SE sites have this link a bit shifted ot the right, or with a totaly different style in some cases (Gaming.SE)