If you are ever considering carrying a front load, a steel fork will be better. There are a few carbon forks with braze-ons designed to add racks, but very few. You can use p-clamps on steel without worry (don't crush the carbon), or could have braze-ons added.

Plus, I don't trust carbon forks. I saw a heinous carbon fork failure crash. Even the modern carbon experts say that carbon fiber isn't a lifetime material, whereas steel is.