ouch on the "isms" thing. I'm new to here, and am enjoying the conversation.
I hate to say it, but I honestly believe that theory affects how we teach, which in turn affects our students. We either try and stay in touch with what is going on in with new theories, or I'm afraid we lose touch with more than just the latest theory.
Postmodernism, deconstructivism etc...They are big words, but these words reflect a mindset of our culture(s). Our kids are postmodern. They're living it. If we can't relate to them and where they're coming from I think we're gonna have a hard time teaching them.
So I'm not as eloquent as some who write here, but this is what I truly believe...