I was asked yesterday if I was a designer and I honestly stuttered, answering "no." I'm not, in fact, a designer. I don't know how to properly use Photoshop to mock up user interfaces. At best, my mockups are either low-fidelity pen-and-paper or pre-made widgets in OmniGraffle. However, I have designed apps.
To me, designing was a process I went through as I wrote the app. Not the best approach, for sure, but I learned so much. Now, while I'm a developer, I contribute to the design of apps I work on. Having an appreciation for the aesthetics of the app I'm writing and a technical knowledge of what's possible (and long it takes to implement) let's me contribute creatively to the projects I work on, and that's exactly what I want.
When I finally answered the question of "am I a designer?", I said "no", but a qualified one: "No, I'm a design-centric developer."