Hey we have almost the same kitchen layout! I would take a cabinet door & a dark knob/pull to a stone yard and see what looks good. There are so many counter choices out there so sometimes it just takes seeing that one stone that fits your vision to pull it all together.

I think you can combat your worry about "washed out" with wall paint colours and accessories. I like the Taj Mahal and I also like the Silestone. I assume you are aware of the upkeep and maintenance issues that marble brings - although it really is gorgeous. Look for posts from Beth H who is amazing at offering really lovely choices for tile. Tilebar is a great place for choice and they have a good sample policy so order a few in and see what you think, but choose that after you've finalized your counters and they are installed. With either the Silestone or the Taj Mahal, you may be looking for a light grey tile for your backsplash. Of course, there are other colours you could choose from too and maybe a more colourful choice than grey will help you get over the worry of the room being washed out. I'm finding that my own preference is longer tiles, not just the regular 3 X 6 subway size but something a bit more elongated. My all time favourite though is herringbone. I know the choices are overwhelming, but do some browsing in Houzz pictures and see what really jumps out at you. Think about what makes you happy, rather than worrying about making the "right choice" or worrying about resale etc.

I think we are moving in the direction to do the island, perimeter counters and backs splash (all the way up the wall) in the same White Santorini Quartzite. Any feedback on this? Im sensitive to adding too many different materials into the mix. Is this too much of one thing?

Thank you everyone who responded so far. I really appreciate it. I would really appreciate If anyone can also share some good subway tile examples that may go well in my kitchen. Also, I was thinking about getting a single quartz stone just to avoid the too many grout lines (May be white with some brown/grey vein). Do you think it will look good?