You might want to use xcin for zh_TW locale. But simplified Chinese
is more common online these days.
I tried both and found chinput more convenient featurewise. My
Chinese class uses traditional Chinese, and I'm going to work with
Classical Chinese, for which I guess I'll need traditional
characters, too.
BTW: A better pinyin input method might be SCIM, see the previous
posts on this list about that.
I don't like the fact that SCIM's pinyin module is non-free, and
that SCIM seems to be more of a moving target, under heavy
development.