As other posters said, it is a subject that generates a lot of strong opinions.
Carbon is the future, but I think that we are still on the bleeding edge in terms of development.
Titanium is a known commodity, in the traditional alloy (3.2V) the tubing and welds are great by top manufacturers like Litespeed. The 6.4V utilized in the Ghisallo is superlight but the manufacture is a bit different.
I test road a lot of carbon bikes and spend a lot of time on fat tube aluminum (cannondale), almost 20 years. In my view, the Ti bikes (3.2V) being made by the better manufacturers today are superb for recreational cyclists. If you go down on a new Ti bike, it will be completely unharmed. Most of us will crash if we ride enough miles. The frame requires little maintenance beyond soap and water. Geometry and fit are huge factors for comfort, but I have yet to hear someone complain about the comfort of their Ti bike. Aluminum ride quality is hugely dependent on geometry. The old 2.8 first generation Cannondale was a stiff unforgiving bike.