I won't lecture you then.

On youtube now is an outstanding Keynote by Donald Clark at the recent Alt-C conference. It's well worth the watch. In it, Clark skewers many of the myths about the lecture, and does a fairly comprehensive debunking of it as a means of teaching.
If you are in the business of delivering long lectures, take note. Some points that struck me to take away for actual practice:
1) Keep talking to short blocks - 5-10 minutes, never beyond 15. No one is that good, not even Donald Clark.
2) Record it and make it available for review.
3) Give out all notes and materials ahead of time. Good students will review them.
4) If you must use slides/powerpoint, learn to use them properly. Simple visual, minimal text.
5) Use in class time between talking 'blocks' for group work, discussion, practical problems etc.
6) Use feedback tools like clickers of short quizzes to assess comprehension as you go along. If comprehension is good, move on. If it is poor, slow right down.
7) If there is good material on your topic in the public domain already, iTunesU, youtube.edu or wherever, use it, or refer your students to it. Optimise your teaching time and don't bother developing or delivering material that someone else can do better.