Rachel,
great post – very interesting to read your views as a developer on this debate. I’m a webdesigner who handcodes, working on mainly smaller sized projects though I do work with developers for any larger scale projects.
And though I also agree with Mark’s view – I think that as a webdesigner, knowing how your design will ultimately be realised is essential. And not only that – the debate ~ from the bits I’ve read anyway ~ has left out how much inspiration can come from knowing your code. It will not only make you a better designer – it will in fact open new avenues, new design angles and make the entire process from design to final site so much more efficient and fun 🙂