I'm going to have to complain about the font size to start with. I know there's a lot of info, but it would be much better to give it some breathing space (if it needs it) than to shoehorn it into a smaller space. When I zoom in enough to make your font size the same as my default (two hits of CTRL +), I get a site that, while still orange, is quite readable and navigable. (You're using a CSS setting that made a whole lot of sense ten years ago, when 1024 x 768 was the "universal" monitor size, but you had to allow for stragglers with 800 x 600. These days the pixels tend to be smaller on any given monitor size, so the fonts need to be bigger.) 100% is small enough these days.
And I'm not sure you want to stick with Verdana either -- it's not a bad font, but it was the default font for so long in the early days of CSS-driven design that it immediately screams "old" now. There were two reasons we used it: one was that it read well at very small sizes, and the other was that it wasn't trying to be Helvetica (like Arial was). Over the years, though, it became as obnoxiously ubiquitous as Helvetica ever had been, and with the current requirement for larger type (and yes, I'd be comfortable calling it a requirement), its relative width and x-height compared to other sans-serifs isn't the advantage it once was.
Your site's main div is locked at 770px wide. On most monitors, that's a little on the narrow side these days. Not that there's anything wrong with narrow when it looks like it was done for readability/line-length reasons, but when it looks like it was done to fit the site on an SVGA monitor, again, it looks like an old site. That might not matter if you were in any other kind of business — selling fasteners or lumber, say — but as a computer consultancy, you're going to want it to look like you've done something to it recently. Heck, if all you were doing was hardware it wouldn't be a problem. Unfortunately, tech, advertising and design are industries where the cobbler needs to have new fancy shoes on at all times. Everybody else can get away with just doing great work for their clients. I'd probably go with setting a max-width to constrain the line lengths on larger/wider monitors and a horizontal padding on the body to ensure there was a minimum "margin" at smaller monitor sizes if I wanted to retain the overall look.
There is a single common theme here: the site, on its face, looks old — and not in a retro or hipster way. And you're in a business that pretty much depends on being up-to-date and current. It doesn't matter that everything you offer is brand-spankin'-new and/or bleeding edge if the user's immediate impression is "to old; didn't read". You need to keep them away from the back button long enough to see what's on the menu. A little work, comparatively nothing in the grand scheme of things, on the CSS will do that for you.
I don't think it needs anything really radical; just poking at the existing CSS in Chrome's Developer Tools (trying a couple of different fonts and making some of the size changes I noted above) livened the place up quite a bit while keeping the existing "brand" going. It's a fundamentally good site.
Because you've made good use of markup and cascades, what's needed amounts to little more than a tweak or three (as opposed to a redesign). You might have to resize/recreate a graphic or three at most beyond a short session with a text editor.
(For any of the kids watching at home, there are some very, very good reasons for getting the content right and separating markup from design. A site like this one can get a radical overhaul in appearance without actually doing anything radical.)