ok first off its a nice layout - easy to navigate - doesnt not render the same in ff or ie particularly the navbar. You may also want to move it from tables to pure css (youll find that managing the layout will be easier) you have 21 validation errors for the html and 5 for the css.
It might just be me, but it drives me wonky when I see a site and scroll all the way down to see the bottom area out of line. That one small banner all by itself is just razzes me I think. And it looks pretty fine in Google Chrome, but sorry I did not check the others.
Please your clients & thank them from time to time.......they are just like groupies that keep the band going strong.