Definatly lacking zing. First try to establish colors for your sites design. Next, tweak the ads and text on your page to fit that color scheme. Then, play with some fonts to clean your page up a bit. Best of luck.
Run spell checker on the page. The image link on the top is brokem (X). Do see the google heat map for positioning ads. https://www.google.com/support/adsense/bin/static.py?page=tips.html
you might want to use a CMS ... maybe wordpress. I've never used it, but people say it's easy to use. I suggest wordpress because this comes across as a blog to me. as you're advising about where to purchase custom-built PCs then why don't you become an affiliate with some PC vendors and drive traffic their way? make some $$$ from referrals as well as google ads. However, the domain name could make a great name for a custom built as in modded PC site. Lots more potential, I think.
As a previous poster stated, severly broke in Firefox...see attached. Desperately needing some images IMO
also with my forum- how do you get google ads on top of the forum? http://bestcustomcomputer.com/forum/
Nice adsense placement and blending, but there are some broken links. And I believe it's good practice to have consistent color scheme across the site. Just some little thought. Hope you go well with your new site.