Should I buy a carbon-fiber bike?

Absolutely. Maybe. Unless you shouldn't. Carbon is generally lighter than other materials, can be constructed to provide specific ride qualities in ways that metal tubes can't, and offers unlimited tube shapes--aero or just freaky cool. If you race and want a super stiff frame, carbon offers the best mix of low weight, aerodynamics and drive train stiffness without a buckboard ride. But it's also expensive.

And not all carbon is equal: Less expensive bike frames use lower grades of fiber, which are heavier and less stiff, and often have a dead ride quality when compared with higher-grade carbon.