Rounded corners and stuff like this is not what flash is meant for, and these applications will die off very soon as more advanced CSS and HTML 5 kicks in. Where Flash really has advantage now is applications with very rich GUI, non-trivial user interaction (drawing, messing around with many different elements in various ways, rich maps, etc.). Now, you could probably make most of these things in HTML 5, but since Flash has tools, libraries, widgets, experienced developers and so on, it would take time until the same is developer for HTML 5. So if you're starting the project right now you may have better luck with Flash (if you task indeed requires the power of Flash - if you just need video/some CSS, go HTML 5), but that might change in a couple of years.