I'm not sure if this is open to suggestions/criticism but here goes:
1.) You're very close to having a valid site http://validator.w3.org/
only 4 errors on the home page all pretty easy to fix.
a.) The only reason I bring this up is because it seems like usability is important to you in looking at your code, you've already spent a decent amount of time on usability (conditional comments, fixes for png's on IE, etc...
2.) Why are there two search boxes?
3.) Don't know if the site is complete yet, but widgets is a broken link from the services menu.
1.) The site looks very good without css enabled (most don't bother with this)
2.) You used ul and li for your main navigation, thats awesome for search engine visibility.
3.) The navigation structure is easy to understand, and the page's don't have complex urls, this is great!
4.) I like the look, it has a good use of negative space and isn't distracting.
5.) Load time is very good, and it handles well across platforms and browsers.
Not many really. I would use more semantic tags in your html to define what the data is, this will improve your search ranking.
use h1,h2,h3 for headings, this helps search engines build an outline of your pages content
use p tags for larger blocks of text, not divs
use span tags for inline text formatting like bolding and italics
Other than that, this is a lot nicer than some of the sites that come through here, good job!
*EDIT: Thats a very good price for such a technically sound web-site.
Also, what language are you using for the form?