[Retric]

I would suggest that Apple is useable because they don't need people to navigate a wide range of products. Just ~7 top level items, then get more specific.

  Download, songs.   
  Buy, iPod
  Buy, MacBook Pro

And then they get a world of options. Amazon is stuck because, most of their options don't really help. I want to buy Electronics, Home Appliances> Air Conditioners, Fans & Heaters> Space Heaters > (Showing 1 - 24 of 1,338 Results) now what?

While I do most of my shopping at Amazon, I think the sight is clunky but functional. Type what you want into the search bar or pick one of the nice pictures that looks correct, and is in your price range. Granted it works, but it's not really elegant.