Responding to David & Josh : is poetry "words" or "imagination"? I think people get caught in such debates because poetry is a unique amalgam, a fusion, a monstrous birth.
First of all, poetry begins, not as words, but as "speech". Speech, language, as Wilhelm von Humboldt argued back in the 19th century, is made of sentence-streams, not individual words. It's essentially MOTIVATED, impulsive - motivated by sense-experience, visions, desires-impulses which are pre-verbal or meta-verbal.
But in the process of becoming poetry, this speech-impulse does indeed become ALL WORDS : poetry has a fundamental ordering or aesthetic motor which rounds out or includes or shapes all these impulses into a coherent, finished work of art. The finished product, like Keats' urn or Eliot's chinese vase, is a magical verbal container for the initial impulse(s). Maybe it could be conceived as a kind of energy-transfer packet.
The langpos mocked the "uncritical" speech-motivation of mainstream poetics, with their technique of isolating the verbal texture from any clear motivation. But this scrambling was obviously symbiotic/parasitical with that which it criticized; elliptical langpo was folded, doubled over "straight" poetics. Moreover, langpo's impulse to discourse was just as "motivated" as the ordinary poetic impulse - though it was an impulse of reaction or negation or separation or alienation or distinction : it's just that the speech-impulse was programmatically scrambled.
In my view individual words themselves are bundles of potential motivation, potential energy. The imagination is a kind of binding capability, inherent in the mind - creating vision, order, coherence, awareness, clarity, observation, etc. When the receptive faculties of the imagination are motivated to respond, to articulate, to give back - then we have the poetic impulse.
Mandelstam, in his theoretical writings, talked about poetry as the intertwining of two strands : the verbal material and the impulse. I think a poetics ought to keep both in mind, & recognize how the impulse creates verbal coherences or contained "light", in the finished work. Ultimately this dual sense of poetry, it seems to me anyway, has more relevance for the social-political role of poetry in a culture at large, than a dialectical spin on the verbal material alone (as in langpo).
Language poetry shouldn't be singled out in isolation, though. There's a much broader stream running from Pound through Williams & the Objectivists & others which tries to avoid the "lyric subject" through inclusion of chance items, found objects, documentary material, reportage. Elizabeth Willis's essay on Lorine Niedecker (linked here a few days ago) deals interestingly with this.