at the very least, maybe we could learn something about ad placement from google.
lots of people have banners occupying the top, but google keeps virtually the entire top third of the screen ad-free.
They also give you virtually nothing to click (or even to read) in the top-third of the screen, until you get to the ads.
at least 80% of that top third is just white-space.
i reckon them making those links at the top into a black bar is clever too. because it kind of merges into the browser furniture. most people will become blind to those and think that the page starts at the white area. They are basically hiding another 9 links -- making the ads stand out even more.