I dig darker-themed websites, but typically favor them when working on more artsy websites. For customer-facing websites I don't find it particularly appropriate. I've learned through a number of marketing channels that people typically prefer lighter-toned websites. It's more inviting and more comfortable for them, and I suspect a lot of this is just due to the implied positivity you get from light colors vs dark colors. It's also better to put blocks of copy on light backgrounds, too, as this type of contrast works best for the human eye.
That all said, this website seems fairly run-of-the-mill. It also looks like a template, considering all of the lipsum going on. My eye is very immediately drawn to the white server pictures, but when I look at them I don't find anything special going on. 3 "server" pictures (they don't really look like that, btw) against a stark white background...it's just too empty. I would love to see a little bit more visual embellishment happening here. Maybe even swap the placement of the servers around to the left, then align the copy to them. They way you fix the split-focus thing going on between the picture and the type.
The logo is also crummy. Just gotta say it bluntly. This client needs a better logo that actually means something. The logo is also lost up there with no contrast to help it pop, but in a way I don't blame you for hiding it. Similarly, all of your black-on-gray links (like "microsoft" in the top-right) are practically invisible. Might as well make it black on black.
Like you said, the navigation is simple, so that works well enough. The Request Callback button stands out a bit too much against the otherwise mundane buttons next to it, though. If I didn't know any better, I would assume your client is selling callbacks. If that's not the case, it might be a good idea to make the main points of sales-driven entry brighter. For example, if your client is selling products on the "Services" page, make sure that button stands out to help drive people to it.
Lastly, I also have to say that the little stock photos being used within the 3 columns are too stock-like. Maybe I'm just jaded. I've just worked in this industry so long that I've tired of the typical stock photo look. I think the public has, as well. The public is more savvy than ever before due to the quantity of imagery they see daily, and so I believe it's better practice to use more natural-looking imagery. Stuff that wasn't taken by a "professional," but certainly not amateurish. Stuff that looks creative and real without looking lame. Dig around on veer.com and you'll see what I'm talking about. Lots of cooler stuff there.
Nice work! (my apologies for my bad english) i don't speak english and couldn't understand complety what $liquidsoft said but, he is mistaked about the eyes. The eyes works with light, right! a few light strain the eyes, but too much light too. The eyes works better with contrast, but as the light fron the monitor is... ..so shiny at time to see clear. The eyes always gonna work better with dark contrast instead of light contrast. more than ever at time to render images and videos. i.e.: YOUTUBE, if you gonna see clear you have to increase the shine then strain the eyes, on the contrary, if you gonna help help the eyes, the render of the video is so much dark to see clearly. What will be about youtube if at least the background will be carbon? Black is bad for the words. White... (go youtube in check out), the dark greys tones are the perfect mixture between words able to be read and images clear to see. A mistake that i've be seen is grey or black backgrounds with LITTLE GREY words. These sites will be more easy to read if they use White words, or even better shiny green, shiny pink, shiny yellow, etc. Devianart, yeah this site, don't use the contrast so goog too say, that is the problem with deviantart. It's like if dude between the lighter or darker, punctually the lighter grey and green words. The background is friendly for the eyes but not the words. i'll put bold shiny lemmon words for the titles, buttons and links (i.e.), or background's buttons much more darker. Another example are the scrollbar's skins IN EVERYTHING, i do see ALWAYS scrollbars lightless, not bad for the eyes in this case becouse is a little area, but are skinned entery lighter and it's hard so find where the F**K is the scroll. Lets talk about the desing programs, some of the most popular companies (i.e.:adobe, corel, ....ACDSee..), what happens? these companies did give account that is better for the eyes render images and video in darker backgrounds, so they skinned they programs in carbon.