I think that you should always try to plan your apps for scalability.
in reply to Are you coding websites for massive scaleability?
Some time ago I found myself rushing to rewrite a badly designed application of mine because I never thought that it would need to scale, very bad experience, since then I always try to make my applications as scalable as possible.
I like to use CGI::Application as my framework along with HTML::Template. I find that it makes it very easy to organize the code and adding things it's not problem.