I had the same thoughts before reading everyone else's posts...The 3 x 6 is more 'standard' and traditional, while the 4x8 would be a little more unique and bring a modern or industrial twist or zing to your kitchen...which I can like with traditional elements. Depends on what you want it to do. And Plllog does have a point about smaller tiles fitting in around things better, but I wouldn't necessarily let that decide it for me. Will one fit in the spaces using whole tiles, while the other will require cutting all the way along? (Remember to figure in grout lines) Even if I liked one better, if the other fit in whole, THAT could sway me to change my mind.

Both will work - you have great taste. At first I thought I would prefer the one you do, the silver birch, because it's warm tones echo those of the floor. But when I put the elements next to each other, I prefer the contrast shine, and stronger colors of the chalkboard. It has warmth, whites, greys, metallic sheen, and iridescence. Your granites call for a statement bs, something a little bolder than the birch. Either way, you have grey granites, white cabs and a grey backsplash - what other paint are you going to use? The birch limits you to earth tones. The chalkboard opens you up to earth tones, shades of white, taupe, copper, greens and even purple. I understand that you want to keep things neutral to offer you the option for change in the future, but the one thing your kitchen could use right now is a color other than grey. BS tile gives you the opportunity to add some now, not just some day. Here are two glass mosaic options that harmonize with your greys but also add a lot of needed color, and will animate your space. Choosing either could narrow you paint options in the future, or open them up - depends on how you look at it, really. http://www.glasstileoasis.com/item.asp?item=13181 http://www.glasstileoasis.com/item.asp?item=18123

For practical reasons, I don't like marmo click in the kitchen, the reason being that the layer of lino on top of the cork base is very thin, and I've had some gouges/dents. Now that I think about it, the gouges didn't penetrate to the cork, but it just seemed like the cork was too soft for a kitchen application. One of my friends also had click in her kitchen and said she wouldn't do it again, for the same reasons I mentioned. So, I would recommend one of the options that includes the sheet marmoleum. I like it paired with the funky yellow and white BS. I also like the idea of a plain yellow backsplash--it creates a nice chunky colour -- I think the term is 'colour blocking'. Slightly warmer than than the straight white BS. Really, I like all your options :-) but I highly recommend marmo sheet rather than click. You can do 2 graphic elements as long as they are completely different in scale (this is what I read somewhere). Marmoleum feels and looks wonderful!

Someone else just posted a completed remodel with that same last tile I think. It looks really cool if you have a big enough wall space for it! https://www.houzz.com/discussions/6201378/the-remodel-that-took-a-year