1. Header. It looks like a banner ad. you might try coming up with an actual logo for the site.
2. Connect the header of the site to the rest of the site. Right now there is a space between the header and the content with your main navigation in between (Home, Forums, etc). This is one of the reasons your header looks like a banner ad I think. One way to connect it might be to take that top nav and make them into images - a navigation bar that connects the banner to the content below.
3. You have a lot of space on the left for the navigation, which means you should not have a problem adding some space between the links - some line space. I would recommend this. You are using a small font, which is fine, but the lack of line space puts these small links close to each other and it is going to be difficult for some to read - or annoying at least.
4. Using "bold" as an over state for navigation... I've never really been into it. It makes things visually jump a bit too much - it's distracting. I guess what I'm getting at has more to do with the top navigation as highlighting one item adjusts all those to the right of it over a bit. I would recommend using only the underline for the hover state and perhaps change the font color from white to a very light grey (again, for the hover state).
5. Consistent page headers. The "Playstation 3 Intro" link (for example) has the header centered, while the "Cell Processor (Part 1) " link has the header aligned to the left. I would choose one (and recommend left aligned) and stick with it. Also, some headers are images, others are text.
6. Consistent content aligning. Most pages have content aligned to the left, but you have a few where the content is centered which doesn't look very proffesional. These pages include the SPE page and ATI processor.
7. Margin. Your content pages could use more margin on the left and right sides. On some pages the text gets a little too close to the edge in my opinion.
8. The welcome text portion... "Please take a minute to signup at our forums." at the top should link to the forums, or to the forum sign up page.
9. Your site is about the PS3 vs the XBox360. It's about comparison. I would recommend not having seperate pages for the specs. Instead use one page and stack them next to each other for comparison. Perhaps using green check-marks to show which is better for each item. People visiting this site probably have very strong opinions one way or the other about which is better - so lining them up against each other might be fun - just an idea.
Anyway, I think it could be a very fun site and wish you luck in getting it up and going