577.59 is an affiliated seller, The Price Pros. Amazon's own price is 499.99 (but sold out). Unless they really are punishing you for returning goods ;-)
FWIW, last week I ordered a Hitachi Deskstar 1TB drive through Amazon for a about $10 less than Newegg, but the price is now the same on both sites. Newegg has also dropped the shipping charge.