I have the same quesntion, can i develop a full site using FLEX ?
It depends what you want the web site to do.
If you want a static web site with non-changing pages about your products or company or self, then you could do it in Flex. However, Flex is probably overkill and you're less likely to get your content indexed.
Flex really shines when you're building applications for the browser. An e-commerce shopping cart may be one example. In such situations, the Flex side of things will most likely need ot integrate with some backend, so you'll most likely need an application server in the backend; such as ColdFusion or a PHP or a J2EE server or .NET
so am i to understand that if i buy a template like this one:
and add a products page to it, it will not get indexed because its a flash site ?
Depends on how they implemented the code and how the data is populated. But, in most cases that is correct; content in a flash SWF is not indexed.
If you google Flex SEO or Flash SEO you can find other information on this. Ted Patrick had a few blog posts on this w/ the Flex Directory app he had built.
It doesn't change things from an SEO standpoint, but I'll add that the template you are referring to is built in Flash 8; not Flex.
Thanks for the informative help.