Are the cabinets are a gloss grey or off white? Not easy to see from the pic!
Your main feature would be the worktop as its very bold. Going too over the top with tiles would clash. I think for the floors a light grey porcelain tile would work well. It would compliment the units.
If you have a fairly small kitchen go for a rectangular tile (30x60cm) and lay third bond. This would help make the room feel bigger. Personally I'd go for a matt finish in a kitchen as theres a high chance of spillage! Have a look at Porcelanosa Zone Nature 29x59cm. There are a few online companies offering good discounts on there range.
As for the splashback I'd go for a white gloss tile laid brickbond.