Sheldon Brown explodes some common misconceptions about frame material at:

Sheldon Brown Frame Materials Link

In a nutshell, he explains that the materials in and of themselves do not create the various ride characteristics, but rather the engineering does. Different materials have different properties, such as strength-to-weight, stifness vs. cross-section, etc. Thus, how you engineer frames to account for the properties of their materials determines how they will perform.

Although I agree in theory that frame characteristics cannot be solely determined by the properties of the raw materials used, and that you can engineer the frame tubes and construction to accomodate the materials, in practice my guess is the way most companies happen to engineer their frames will generally lead to the stereotyped characterists, e.g. that an all-aluminum frame will tend to be relatively harsh.