If you've been reading me for awhile, you'll know I absolutely despise Flash intros. I'm going to a site for a reason, and it's not to sit through your commercial twiddling my fingers waiting for your home page to load so I can get done whatever I went there to do!
That said, I am exceptionally impressed by the Flash intro at CorporatePlanners.com
because they've used the Flash to present the most powerful marketing tactic of all -- happy client testimonials. It goes on for a bit too long, and the site afterwards is pretty blah (I'm so bored of that handshake clip-art), but then you can't expect me to be 100% enthused about everything can you? Anyway, if they cookie visitors so you only see the Flash intro the first time you enter (and don't have to sit through it again and again as an ongoing client or prospect) then this would qualify as one of the best Flash Intros I've ever seen.