Yes its way to narrow, im not website design expert but they should be able to use some sort of cookie or script or something detects the persons screen size and adjusts the site accordingly.
Also if your going to use a left side menu it should be broken down into more catagorys since theres more room now having it on the left. Also subcatagorys listed horizontal now just doesnt look right do to the space the text takes up, doesnt align well. These catagorys should also use buttons of all the same size, similar to the left side main catagorys.
I think the stats of a couple years ago 800x600 was the norm, but not now days, 1024x768. They can hire tons of great web designers that doesnt make it great. I suggest they take some cues from a site like directron.com wich is a DIY yahoo marketplace site (LMAO). But it works, works well despite its very simple and boring layout and it being a bit crowded. Some of my favortie to navigate and use computer hardware merchants use yahoo. Coolerguys, sidewindercomputer, nexfan, svcompucycle etc.......
Oh and.... my usual rant about newegg, BETTER SPECIALS!!! your specials just arent special enough! LOL .. You basically have to give away something for free and ill buy a bunch of other stuff with it that I need anyways because of shipping, thats how it works. Charging flat shipping rates for each product and not a total purchase shipping rate really hurts business. If I buy 20 products your not shipping 20 different boxes, its one box and shipping is cheaper for newegg itself, pass that on 2 me the consumer.
So somebody from newegg get your a** over here and read this