Google Docs/Drive is a great, free resource that allows you to create, edit, share, collaborate on, and comment on Documents (Docs), Spreadsheets (Sheets), and Presentations (Slides), all online. Think Microsoft Office in the cloud with some other great features.
I use Google Slides (Presentations), the equivalent of PowerPoint, for all of my presentations. I like the features it has and like that I can easily share it online and people will always be able to see the newest version. One downside was that you needed an internet connection and some conferences I have presented at can have WiFi issues due to all of the devices being used. I would always save a copy of my presentation as a PDF file to my laptop in case I didn't have a good internet connection. That is no longer necessary.
Google has announced that Google Slides will now be available with offline support. You can now create, edit, comment, and present your Slides presentation without an internet connection. When you get an internet connection, your new presentations or changes will be automatically updated online. Docs has had this for a while already.
This is a great feature that makes Slides even more useful, along with Chromebooks, for people who need to work on, or present, their presentations where they may not have WiFi. It's also great for schools who issue Chromebooks to students that may not have internet at home. Our district is going with Chromebooks and student internet access at home is a concern. That is less of a concern now.
To enable offline Docs/Sheets/Slides, follow these instructions. If you already have offline enabled for Docs, you are all set. In order to use the offline feature, you will have to use Chrome browser or Chrome OS.
Google is currently working on offline support for Sheets as well.
Offline support has been the one reason I see many people stating as why they won't or can't go with Google Drive/Docs and Chromebooks. That reason is disappearing.
Google for Educators Resources