Simon,
Just had a look and I do like your pictures but I am not that keen on the theme used of the site.
(a theme is the general look, collection of buttons, default layout etc)
The main title does not really stand out at all, you could use the whole page width and the font chosen is rather boring. Do you have a logo for your company name? Maybe done as a bitmap. It just needs to stand out more and done like that it just looks more professional.
There is a problem on your home page (at least in Safari):
The theme you have chosen for a menu does not make it obvious that you have a particular option selected. I thought that this was a fault (to begin with):
I appreciate the reason for using grey, grey, black and white but it just needs something to make it pop I think. The background is a little dark. The about page is just a block of text, again just black and white.
[from Mrs Cowasaki, can you graduate the centre in the reverse direction to the background graduation. She thinks that that might help]