Not convinced yet? Here are a few reasons to hate Flash:

1. Users hate it. Maybe you are interested in dumping a lot of time and money into creating a cool animated introduction. Don’t bother! More than 80% of those surveyed dislike flash intros and more than 60% will either skip the intro or leave your site entirely when presented with a flash intro. You are lucky if they even stay through the annoying loading symbol. With a slow internet connection that could be quite a while.
2. How cool to have a site that plays music? Not cool at all! In fact, research indicates people do not like automatic music playing on sites. Many people are at work and don't want to disturb their coworkers. Also they might be playing other music or not have speakers. Often times it is difficult to turn the music off as the player tends to be slow to respond. And if you have to return to a site multiple times (which should be your goal for your user) they are likely to be annoyed by the third time they have to hear the same song.
3. You can’t use it on iPhone or Ipad. We don’t blame you, Apple.
4. Search Engines can’t find the content on Flash so you are basically killing any chance at good SEO.
5. Flash plug-ins are generally are hard to navigate.
6. They break easily. When this happens they are hard to fix by normal site administrators not trained in Flash.
7. It is difficult to manage changes to anything in the Flash animation.
8. Adobe has even announced it is abandoning Flash in the next couple of years – knowing that HTML5 is going to be able to produce video and animation options that are far superior.

There a few places where using Flash is appropriate but they are few and far between and mostly have to do with web applications. My general advise is to avoid Flash at all costs.