Flash content such as intros, animations and redirecting the user via Actionscript as well has it's SEO drawbacks. Once again, no rich content for the search engine spiders and the Actionscript never executes for the spiders to find the rest of your site.
There are a few method of making sure your users and search engines do finally get to your site but in the end you're setting yourself up for trouble. Splash pages were a good idea when Flash first came giving some kind of intro animation and something cool for the users to look at and in the end the users would tell others about the "cool site they just saw". Now that Flash has been around for a while search engines and SEO methods are king in getting traffic and keeping it. If you can't be found on a search engine chances are you can't be found and no amount of cutting edge animation or fancy flash will help that.
Clean code, relevant content and steering away from tricks and hacks to get traffic or entertain your users is always a good standard. Search engines not only like sites that follow the rules but they are usually rewarded with interested visitors and higher rankings.