Apple Keynote - Apple Keynote or just Keynote is an advanced level presentation software application created as a part of the iWork productivity suite by Apple Inc.
Prezi - Welcome to Prezi, the presentation software that uses motion, zoom, and spatial relationships to bring your ideas to life and make you a great presenter.
SlideShare - Discover, Share, and Present presentations and infographics with the world’s largest professional content sharing community.
Slidebean - Presentations that design themselves
Ludus - Limitless creativity for your slides.
Zoho ShowTime - A web and mobile app focused on making better presenters out of speakers.