I really enjoy using Reveal.js for my presentations because it allows me to display code side-by-side with working or interactive examples. It also allows me to easily embed media and work in a format that I am familiar with. It is also extremely convenient to host and share the slides through github pages, allowing me to provide this url to atendees or others that may wish to reference it later.
The image referred to for the body background I saved from here and I popped it in the
img directory within my reveal project.