It's funny how anti-carbon people are, without realizing there's a reason why everyone uses it: strength. You think track racers give two shts about weight in comparison to other factors? No, it's strength, and stiffness that matter. It just so happens that you can achieve many times the strength of other materials for a fraction of the weight, without rider weight limits like in Ti.

As for "catastrophic failure," you do realize aluminum only bends once, right? Then it snaps? And that the joint between aluminum and carbon is going to be weaker than a solid piece of carbon? If water enters the carbon matrix and the carbon isn't properly insulated (fiberglass), you'll get some nasty galvanic corrosion (hell, without insulation you'll get it without the water).

If you can afford it, go for the cabron steerer tube. You'll have to be a little more careful with putting on the stem, but if you're not a ******, it'll give you a stiffer, yet more shock-absorbing ride.