Here is an almost sure recipe to get a good look and feel for a presentation template, even with an Arial font:
  • One nice accent colour, but used sparsely for only that: provide an accent
  • The other objects in shades of grey, using relatively more light ones than dark ones
  • Text in dark grey, not black
  • No lines around shapes, let the color (i.e., grey) do the work
  • Everything flat: no shadows, no gradients, no reflections
  • Black & white images only