Why such dull colours? Oh I forgot, it's created by programmers :-P
I'm not by any means a designer, but from my art background I can tell you that changing the orange top-bar of stackoverflow, you've caused a collapse of the design regarding the rest of the colours. The design needs the orange top bar and not a grey one.
If there's one thing I hate about programmers (or interface designers) its their denial of colour and their imposition of their insipid dull-arsed taste on the rest of us.