I just came across a website that is designed beautifully but will have a lot of problems getting listed on search engines. First of all, the site only uses Flash for navigation. At this time, search engines cannot read content in Flash files so most of the pages on the site are hidden. Secondly, all the content pages are displayed in a frame. The problem with this is that if the search engine found a content page, there would be no navigation to go to another page on the site as the navigation is not part of the content page. In effect, making it a dead end at the site and the user will have to hit the back button or type in another URL to leave the site. Not a very good eyeball retention technique.
How unfortunate that some very esthetically pleasing sites will rarely be viewed.