These were my fears as well. I recently bought a carbon frame bike. I had cross shopped all brands and materials. After weighing the pros and cons of them all, I choose carbon. Best ride quality, IMO. As light as anything else. Frame guarantees as good as they can get, lifetime on some brands. Just treat with respect like you would any other bike and you should be happy.
I know they can be ruined in a car crash or crashing the bike hard. This can be said about any frame material in general.
Aluminum- IMO, chatty ride, transfers more vibrations. Dents easily. Usually does not corrode. Very light frames.
Titanium-IMO, expensive, hard to find without special ordering before you even see the bike you will be riding/buying. Does not corrode. Does dent, but pretty hard to do.
Steel-IMO, classic material, heavier (usually), good ride quality. RUSTs when exposed to elements.
Carbon, IMO, smooth ride, stiff as they can get. As light as anything else. Sexy tube shapes abound! Have to be careful about scratching the carbon, this may lower Carbon weave integrity. May want to buy a torque wrench. Sexy looking frames! Yes, I said sexy twice. Exposed carbon fiber weave is cool to look at!
Happy hunting!
Mike