Earlier quoted context omitted.
I'm not sure that "plastic" is as bad as popular opinion thinks it is in the case of something the size of a phone. If we say "polymer" does it sound any better? I mean there's plastic.. and then there's plastic.
Of course, it's not necessarily bad, and there's different types of plastic. Some kinds are very rugged. However, most plastic phones are made of plastic because it's a cheap material that doesn't require much in the way of precision to fit together, and it just doesn't have the same kind of quality (or even quality feel) as a phone made with a different material.
Then I got a Galaxy Nexus and revised my opinion on plastic phones entirely, it feels good in hand and has ruggedly endured all kinds of accidental abuse at my hands.