Pinpoint is some pretty fun slide software that I like. Homepage: https://wiki.gnome.org/Apps/Pinpoint

My Slide Software Criteria

• Mostly-live edit, ideally in vim
• Simple markup, ideally diffable
• Big word centered in screen by default
• Not too ugly
• Export to PDF
• Open-source, duh. Ideally via apt-get

Pinpoint additionally has:

• Associate/run a command for the current slide
• Presenter mode (though I don't use this often)
• Easy drop in videos
• Can record the time to help pace the presentation

Pinpoint workflow:

• Copy over a simple .pin file to start along with my boring blue fade background
• Start pinpoint
• Edit file. Saves jump to the first-edited-slide
• Before I present, use pinpoint -o to export a PDF and email it to myself
• Practice practice practice!

There are quite a few setups that meet all these nowadays. But I like pinpoint anyway :)