From useit.com by Jakob Nielsen:
Uncovering navigation shouldn’t be a major task: Make it permanently visible on the page. Small children like minesweeping (passing the mouse around the screen to see what’s hidden), but teenagers don’t like it, and adults hate it.

I don’t like having to work to find things I want on the web. If I go to a retailer’s website, I want to see the products and get a price. Those two pieces of information should practically hit me in the face. But that doesn’t contradict the notion that everyone likes a surprise. Utilized skillfully at the appropriate time, a violation of expectation can delight and endear the child within. Or really annoy the adult without.
