Like the site, lots of good information. But (isn't there always), your home page is way to long - need to keep everything above the fold if possible. Visitors do not like scrolling unless you they chose to do so. Keep all homepage abovce the fold and all will be well.
I would also have a look at your primary navigation. It works but is a tad boring.
There is also a consistency issue. You have an effective header on all pages except the home page - ewhy the change?
Your portfolio has different sites to those listed elsewhere in the site. Consistency again.
However, I do like the site, and the code is really clean which is big bonus in my book.
More to come when I have a little more time.