Search engines believe that
http://www.hugon.ws and
http://www.hugon.ws/default.aspx are two separate pages. They believe that these pages have the same content and this affects SEO.
Search engines will treat
http://www.hugon.ws and
http://hugon.ws as two separate websites. Search rankings are surely going to drop, given that search engines believe that 2 sites should not share the benefit of having the same content.
URLs can be defined in uppercase and lowercase. That means they are treated as different pages by a search engine, even if they point to the same resources and content.