Looks pretty good! In the drop menu the text was a little hard to read since the blue background is on the lighter side.
On the bottom right of the main page you have two boxes with the edges "cut". It would look cool if you took the bottom left of those boxes and curved them like curved rectangles you have. The top right would still have the straight cut.
Very clean and crisp. I like the OS Xish style. It's very smooth with the softer colors but in a few areas the grey text seems a little light. The red text as your highlight seems a little too ... bold? The site is very soothing, then the red appears and stands out a little too much. Maybe try a dark blue or something, not sure. The DHTML menus look fine on my screen except they could all be shifted to the right just a bit. They aren't all directly under the headers (just being picky now). Very nice job though.