I like clean designs, and this is well structured.
Menu system is simple and effective. I would always advise not using all capitals though. Upper and lowercase (or completely lowercase) looks more pro.
Looking through the code, you can tell there are a lot of templated sections in there - but that's no biggie.
One thing that bugged me was the use of multiple font types. You use a distinctive font for the logo (custom?? this is great.) but with Times New Roman as well. You then use Arial for the page default text and yet another font type for the section titles.... messy.
Use of lightbox is clean...
Your site centers around internet graphic design, yet most of the examples relate to what is technically.. fine/ graphic art. Perhaps you could have more examples of internet design, perhaps other layouts?
As for SEO, you need to at least put in a description in your head and your main content titles are using h2 instead of h1.
Your services (.linklist li{}) links with the graphic element on the left need to have more space between graphic and text.
Couldn't immediately tell where the external border is on your slideshow within the css, but I'm not sure it's necessary. Your images already have a grey pixel border, which should be enough - not sure. If you want to keep it clean, reduce... not add.
Otherwise, a really attractive effort.
