Conditional email notifications would be great! Have had multiple requests for that feature, but alas, it's still "future." Count me in as another request for this feature!
Keep it simple at first? Have the conditional email requests a function of just one radio button field. So a single input field drives the logic, and to keep it simple, have only the message field in the autoresponder be the variable output, since we can already customize the heck out of the message with HTML.
My two cents. Keep up the great work...