There are a range complete presentation packages, some are 'freer' than others and some are more versatile than others. With little effort they can give you everything you need to produce a professional-looking presentation. But it isn't about the software. No matter what application you use you can still end up with slide by slide visual aid that sends your audience to sleep. Remember that if you are the presenter, your presentation is merely a tool to support what you have to say.
In this post there are a selection of the alternatives to the old faithful PowerPoint, Prezi and Keynote.
Try this links for size:
You might also try testing some polling system; a great way to get your audience involved, check a few out below: