We vote tiles! If it was my kitchen (and mostly because I'm a messy cook) I would be inclined to tile (or glass backsplash) anywhere that might need to be wiped down-e.g. behind cooker, along any counters where I might be doing any food prep. This gives you plenty of options-you could tile behind cooker and counters in metro/subway tiles, but be careful as it could look busy with the granite and wood grain of kitchen-it will depend on the grout. Alternatively, you could use big clean glossy tiles like this marble look above.

My personal view is that tiles in a kitchen are a harbour for dirt and a pain to keep clean. Smooth, sleek surfaces are best. We went for granite upstands to match the worktop and a contrasting but neutral glass splashback.

Going bold is one option, however i see a  very restfull, clean design. My thoughts immediately went towards continuing with that feel with a tile with only a soft hint of color, a tile with an uneven surface to create movement, or a tile with  'mother of pearl' finish on a soft white to be all color yet none.Your indoor plants will bring live color and not be overwhelmed on busy counter.

There are a huge array of tiles you could choose. Even metro tiles can look good if you choose a nice finish like Zelig, first pic below. Go onto Pinterest or Houzz photos to give you more ideas. I would take them up to that wall unit you have and behind the cooker go up to the hood.