Sometimes it pays to think outside the box. Take a typical PowerPoint presentation. A blank page slide will be set to default as landscape, with sizes in proportion to most screens. However, there is nothing to stop you creating a slide show entirely in portrait format if this lends itself better to your delivery. When presenting a continuation of portrait images, for example, you can select the portrait set up for your slides. The images don't have to be sized into landscape shapes, or have floating hd wallpaper widescreen space around them which might spoil the effect of the composition.
