You're not going to get proper feedback from this forum, since web design is completely different to sigs, the only people I can think that'd give you proper web design feedback would be myself and Jansen, so here you go:
The whole thing is flat, there's little to bring it together. you've got content all over the place, you need to LEAD the user's eyes around the design, currently you aren't doing this. I can't tell what a link is and what regular text is, speaking of which, you can't use just any text for a web design you need to stick to the web safe set, however that being said you can use a technique such as cufon or SIFR3 to replace headings with custom fonts.
You need to think about multiple screen resolutions, not everybody uses the same resolution as you, but it looks to me like you've designed it that way. Also, seperate your headings from the content better, you've got headings smaller then navigation, and headings the same size as your content.
Speaking of the navigation, you're not keeping a consistent look throughout it, some are white, some are black, what shows if I've visited one page and not the other? What shows when I hover? I'd also suggest, considering it's a design for a portfolio, not to include ads, not every site has to have ads, and you've got them smack bang against your logo, which degrades the quality of the site instantly.
Use visual cues as well, you've got ".psd to design" which could easily be improved with a Photoshop psd icon, for visual cues. coding could also be shown with a "<html>" icon or whatnot, and your logo seriously needs work to make it "pop" as it just aids in the visual blandness.
If I get some time, and have the oomph to bother, i'll show you what I mean and change your design around to illustrate my points later on and edit this post with it.