The logo placement is not good - the gradient effect on the nav, get rid of it keep it flat. Make the nav text uppercase instead of lower case.
In the content area, your image headings look like shit, either change to a better font, or just use text headings which will be more appealing to search engines and be more accessible.
Content text, first of all I think that there is too much of it - I don't think people will read all that stuff; try to keep it shorter to the point - point form if you can.
The content font too small, and dont forget to style line-height makes the text much more readable and inviting to read.
Portfolio page, you are making the user to work there to figure out which photo is for which pharagraph. Put the photo beside the description so it is right here and with confusing or any work to figure out which one belongs to which.
Maybe while you are at it, center the whole thing, and drop some bgcolor around the white content area.
Add a footer, since your pages are long.
Hope this helps.
Contact page loose the borders thingies.