I think flash is cool, but it has a lot of drawbacks ... slow load times, problems for SE's, and some people feel that it has security problems and won't enable their computers to "see" flash when they surf. With that in mind ... I'd only use the effect as a compliment to a page that would still stand on its own. Flash as a full fledge site ... I'd say NO ... with the exception of sites that need it for stuff like gaming, in which case, it's assumed the people using the site have the kind of system needed to view it.