What’s a preferred site structure?

On February 26, 2009, Google software engineer Matt Cutts collected questions on Google Moderator and answered many of them on video. Katy Bairstow from London asked: There seems to be little impact on human visitors where in the site’s structure a given page is, so: Is it better to keep key content pages close to root, or have them deep within a topical funnel-structure, eg: food/fast-food/burgers/hamburgers.php