Why just choose one type of stone? Instead, you can mix and match types and tones to accentuate the different shapes in your garden. Create meandering pathways with white stones with larger black stones within to create a steppingstone effect.
Utilise different textures within your garden to create an impact. For example, contrast smooth stones with spiky plants such as Festuca glauca (blue fescue) or Phormium (New Zealand flax).