This is the question debated in many educational circles. There is no doubt that Powerpoint is a useful tool when used creatively by languages teachers. However, interactivity must be the highest priority. I have heard of lessons where Powerpoint was not used at its most interactive, with unflattering-and unfair-comparisons with OHPs being made. Like any other tools, both Powerpoint and OHPs can be used effectively. As we all know it, "it's not the tech, it's the teaching" that makes all the difference...
Edward Tufte, a Yale professor and expert on visual communication has published a number of articles and essays on Powerpoint. http://www.edwardtfte.com/
He points out the following as what a "bad" Powerpoint can be:
*a crutch for presenters who move fom slides to slides and do not get involved with the delivery of their presentation;
*complex ideas being presented in a simplistic way as a list of bullet points, rather than showing the links and hierarchy between ideas;
*ideas being presented in a strictly hierarchical way which is unneccesarily reinforced throughout the presentation;
*concepts being presented in a linear rather than logical or intuitive way;
*Poorly presented and difficult to read slides that make it difficult to concentrate on content.
The way forward could be to:
1. Find out about basic rules to make slides easier to read. For instance, by looking at the ICT4LT as it is a reference for technology use for mfl in general. http://www.ict4lt.org/en/index.htm
2.Ensure interactivity with students by checking length of teacher input and reflecting on its quality. Is it necessary? How can I get to the issue quicker?
3.Adopt a multi-sensory approach to appeal to different learning styles e.g. kinesthetic games, listening comprehensions, include audio to reinforce good and varied pronunciation models, reading exercises using authentic materials, presentations in self access that need to be altered...