I’m a programmer, I consider myself to be a reasonably good one as things go. Which is only to say that when I want to make a computer do something with code I can normally sort it out in a manner that’s more or less efficient. What I’m not is a designer, I know how to use Photoshop and Illustrator as well to a certain degree, but the whole designer thing just doesn’t work.
I’m of the same opinion as Wil Shipley, which is developer shouldn’t try and be designers (Mike Tyson is a notable exception because he’s actually a decent designer as well). To illustrate I’ll use Mosaix as an example. I sketched what I wanted the menu look like, in this case I gave the sketch to Bruce and go back the fantastic menu screen from the app. I’ve even made a diagram showing how it works.