I loved it when lecturers made the PowerPoint slides available before the lecture, as it meant I could read the slides ahead of time and thus keep up in the lecture. It made it easier to take meaningful notes.

I'm somewhat convinced that the average person can't sit and listen to someone talk for more than 20 minutes straight without their mind wandering. If a lecture is non interactive, then just make it available in written form and use that lecture time for seminars instead.