I have bikes made of steel, titanium, aluminum, carbon fiber. My opinion (here come the knives, I'm sure) is that you can skip titanium and aluminum. I love the responsiveness and lightness of my carbon fiber bikes; and I also love the solid feel of my vintage steel bikes. I've never had any issues with my CF bikes and they have held up really well on some not-so-nice road surfaces; and, as was just mentioned, CF is repairable.

I rode on this absolutely gnarly descent today on one of my CF bikes and I was thinking, hmmm . . . maybe I should have ridden my old, heavy Bianchi. Nothing happened because I was attentive and missed all of the terrible ruts and potholes in the road. I think there might have been spots in which, had I hit them incorrectly, I would have broken my frame. But, honestly, I think the same thing might have happened to my steel frame! So, it all just depends.