Looks like Amazon is testing out a new site design.
A few facts from the about page:
What’s different?
We concentrated on shopping, searching, saving, and buying–the four activities that customers have repeatedly told us are the most important to them. They’re now prominently featured at the top of every page on the site.
Don’t worry–we didn’t remove anything. All your favorite features are still here.
Why do I see the new design on my home computer but not at work?
We’re still in our testing phase, and you may not see the new design all the time.