I think your concern of what to call yourself on your resume is very important. I think I fall somewhere in between a designer and developer, taking CS courses and working with user interfaces at work force me into a mix of the two. What I think those who are good at both should do is call themselves by a dual title, Web Designer and Application Developer. I think, and hope, that a potential employer would see that as a great advantage, having someone who can do both, and communicate well between the hard core developers and designers.

Arashi