Constructive Criticism: use a softer background color and consider retweaking the logo: glossy, over-stroked, drop-shadowed site logos imply that startups don't know better and are the epitome of bad design that many associate with "web 2.0"
To be honest I think Stack Overflow needs a bit of a redesign. The fonts are all a bit too large, and it's the same on this new site. The size of the font for the questions titles is too large for me to read the titles comfortably.