Ok, the site is up and working now. I have to agree with the flat feeling. The layout looks great and the color selection is good, but everything just lays on the screen. You need something that makes it pop out a little.
If you are going to use the shadow effect, like you have underneath the menu bar, I would use it for other things too. It looks out of place up there by itself while everything else remains flat. Try it on the menu boxes to give them that floating feel.
For a web design site I think your header is a little weak. You definitely need something in the background, it could be a gradient or a logo to fill in all that whitespace on the right side.
I am by no means a professional web designer. These are just comments from an internet junkie. I've dabbled a little bit in web design, but I mostly use free layouts and tweak them to my liking, so take all my comments with a grain of salt.
Best of luck to you,
-Rock