Just took a peek at the site. While I think it does an ok job displaying your work, I think the color scheme and general look can be vastly approved upon. This is a designer's perspective so brace yourself!
1. Use a more professional looking font.
2. Get rid of the gradient/beveled nav buttons and the beveled box surrounding the content area.
3. If you want to keep the site purple, look at the shading of each area. (for example, look at the shades in this very forum....why does this have a more professional look to it?). Also, it looks odd that the area outside your site is white (outside the table holding everything).
4. You've got some really nice work so let people know that when they first visit the site...something better than the wireframes and renders just plopped on the homepage in the header. Really distinguish yourself in the header area....typography is important as well how you layout your graphics. Right now, everything just looks blocky.
4. If it's a portfolio, put some of your best work rather than overdoing it. I saw one render in the 3D section that wasn't really in the same league with your other work. Right now I think your concept drawings really shine. Just an idea, but categorizing by project might be a cool idea so folks folks could see the evolution from concept drawing to final render, with accompanying text explaining the project and whatnot.
My overall suggestion would be to look around at some of the design inspiration sites like surfstation
or some design blog sites such as cameronmoll
which will link to other design bloggers. The sites these sites link to will give you some more ideas of what modern design is out there.
Sorry if it seemed like I ripped everything apart. I'm kind of on top of design as I've done it for a living for the past 7 years. I just think if you're going to show good work, then make a site to match it. I would really feature your concept art. Wish I could shade and draw like that.
"Terminat Bora Diem, Terminal Auctor opus."