In deciding the layout of your site, you need to decide how deep to make it. A site's depth is a function of the number of clicks it takes to get to any given piece of content. User studies show that with every additional click into your site, you lose a large percentage of your users. But for sites greater than, say, seven or eight pages, it isn't practical to link every page to every other. In general, larger sites should have greater depth and more categorization because even though there are more clicks, it is easier to sift through the information in a meaningful way.
Many clients feel that their sites are ground zero for new users.
Resist the urge to dumb down your site. It's understood that there is a certain learning curve for navigating through a given site. A good navigation system should be consistent. Don't sabotage a user's experience by changing the rules of the game midstream. A well-designed navigation system should eventually become transparent or innate for the user.