Since 1997, I've made my living primarily as a web developer (with forays into requirements analysis and the implementation of software-as-a-service [SAAS] offerings). This is a necessarily partial list of web development platforms or technologies I've used or am currently using. (See also my separate description of my experience with hosting environments.)

I used to say I mostly worked in the presentation layer, but that's harder to characterize than it used to be. When I work on a web project, I'm typically responsible for executing everything that's not strictly visual, but that often includes the interaction design. With more complex solutions like Drupal, there are often a number of critical solution architecture decisions that need to be made and implemented. (Use the Blog module, or create a custom content type and add Views? Code custom pages or integrate the Panels module for complex layout?)

Then there's the data import issue. Legacy data isn't just content -- it's also your old Information Architecture [IA], which has value for its search engine optimization [SEO]. So even if you throw away all the old content, you should still be forwarding your old page names to new page names, at a minimum.