Overall Layout

[waldo]

I think the layout is really clean...I would make one desing change....just a suggestion:

I would lower the top buttons and logo. They look a bit odd all the way on the top of the screen. I would lower them to maybe just above where you get that hexagonical shape in the logo...or is that space intended for advertising banners?
Just a suggestion.

[Reef]

Hmm, I think this is a matter of personal taste.
I really like the blue bar with the big DT logo on it. It would be a waste to put some banner over it.

There's one thing that I'm wondering about... There's a gap in the white line (the one which has the 'Quick links' button on it at the right). Why is that?

Edit: I just noticed that in 800x600 the Quick links button fits right into the gap