I really like the large icons as these will be great calls to action on touch devices – where the input method is far less precise than a mouse cursor. I also dig the graphic used to label the search input for purely visual reason. The gradients could be a little more chilled out though.
If I were to offer some general advice, I’d say that perhaps the reason this is a little tough to critique is that there isn’t that much true content and it’s just a static image so we can’t really asses how well any interactions might behave. Any chance of a web-ready mockup?
I think that’s better (a little simpler) and I reckon you should stick with dark specifically for the gradients, rather than the sandy option. It works well as a complementary contrasting colour though (as in the sidebar).