If you are riding competitively then buying a carbon might be a good idea but if your not then there is no real need apart from the buzz of owning one.I think I will always have a use for the Titanium bike for commuting (because it has pannier racks which I need). My fear is that I will spend £3.5K on a carbon bike but then find that I still prefer the Titanium. I think that that's unlikely and I'm pretty sure that I will prefer the Carbon frame for sportives / weekend riding. However, never having ridden a carbon frame before, I just can't be sure....