If you're using Apple, Keynote is the logical choice. It's really fast and easy while still producing something that looks good, since it enforces some importan

If you're using Apple, Keynote is the logical choice. It's really fast and easy while still producing something that looks good, since it enforces some important rules by default when it comes to slide design. PowerPoint offers slightly more control and a lot more tools, but in general I would create slides in Keynote and maybe pep them up with graphics designed in PowerPoint. If you want to go indie, you can also try using Latex + e.g Beamer for presentations. It's immensely powerful (including video and animations) and can give you highly professional looking slides, but it's also easy to fall into bad design traps if you don't know what you're doing. It also has the steepest learning curve of all three.