If someone comes a knockin’ on your door trying to sell you a Flash site, run as far away as you can and quickly. Adobe wants to own the internet realm the way Microsoft owns the OS market. Flash is sticky, hard on search engines, and it’s ActionScript is just not as scalable as other dynamic languages. Granted, we use Flash elements for nice graphical effects, but even AJAX (think Google maps) is starting to do what Flash has always done.
Flash is good for niche websites and only if in parts on others. Pay closer attention to XML, JSP, and of course, PHP.