A leading design firm uses Apple’s Keynote application for a lot of design work:
One of the most powerful features of Keynote is that is will take virtually any file that you throw at it. Images, vectors, video, audio, etc. can all be simply be dragged or pasted into your work area. Once in the work area, they can be resized nondestructively.
They use it in the idea-creation and mock-up stage of design, and they find it to be a nearly perfect tool for that purpose. My students and I have been using it to lay out large format scientific posters for years, and they find it much easier and more powerful than PowerPoint. The alignment guides that pop up and prompt you make a huge difference.