A recent client was wondering why I turned all images in his presentation to B&W.
The answer: because I matched the colours of the presentation to the colours of his brand; shades of grey plus a strong blue as accent color. These type of colour schemes are actually my favourite ones. They look elegant, are recognisable, and it is very easy to create a harmonious, consistent set of slides through the deck with out the distraction of clashing colours. Definitely not a presentation with a 1980s, pre-colour monitor, look and feel.