Like others have said, frame material doesn't really matter. State what your desire is for the bike and many can suggest the particular bikes that fit that type of riding.

I've had all the common frame materials, aluminum, carbon, steel and Ti and they all rode differently. I've had aluminum that rode like crap and one that rode very, very plush. I've had carbon that rode very harsh and some that were so plush you didn't feel anything. And everywhere in-between. Geometry tends to be the best way to determine how a bike will ride, but carbon it also depends on how they wanted the frame to ride.