My favorite alternative: Reveal.js http://lab.hakim.se/reveal-js/#/ Simple HTML slides with snazzy transitions

Warning: A common pitfall of "flashy" presentations is that even if you can avoid making it look gimmicky, the audience is too busy watching the effects and not listening to you. Is your intention to dazzle people, or optimize the amount of information your audience absorbs? https://www.youtube.com/watch?v=meBXuTIPJQk