No to the grey - your wall seems to have a green tinge in them, so I would say either green/grey or a warm white tile with darker grout. If you choose the right grey/green, it is a classic look so shouldn't date. If you are a bit scared to choose colours, why don't you get a couple of warm white sample tiles and put where the splash back will go. You will soon see if it looks too stark....(maybe another idea, but possibly not a good one - why don't you see if you can put a few pages from a blank sketchbook in the whole area where the splash back will go (not super white white, but a warm white). That could also possibly highlight how stark (or not), the white may look. I can see what design tank is saying, as your cupboards appear to be more cream than white in the photos and if this is the case, then I agree the white will most likely look too stark. My cupboards in kitchen were white (but a warm white not a cool white). The stone bench tops also have the little speckles of stone in them..I can't remember the colour Ocean foam/Osprey.......but even with those colours and them not being cool whites, I thought the white tiles looked too stark against them. I therefore went for a glass splash back and ever since I then went to think of designs for my bathroom renovation, I constantly regret going with the glass in the kitchen and modernising the house too much..........definitely don't do glass if you are wanting to keep a classic charm to the house. In a long winded way, I think yes, I also think you should just stick with the grey/green. It will make a statement. Not the right shade...but another example....it may be hard getting the colour of the tile exactly right given that the walls are already painted and the tiles need to match.

I like the bottom left one in the first pic of the set of three you posted. What colours do you plan in rest of the house? The second sample in your first post has some nice colours that you could pick up as accents.

I'm not much help, just offering an opinion! I think using the same tile on the floors of the different bathroom is good - consistent and cheaper too! Possibly on the walls, depending on the tile, but perhaps the shower tiling and splashback behind basins can be different to provide interest. Inspired Spaces, it's interesting to hear that tilers won't or don't want to lay tiles bigger than 600x300 ... I saw a fabulous tile today that comes in a few different sizes but 1000x1000 is one of them! The one I'm thinking of is 1000x500 for the floor of bathroom and shower. I asked the tile shop that exact question (about being hard to lay) and she assured me the tiler wouldn't have a problem. Maybe because we aren't putting them on the wall? And our floor is 3200x1000 including the shower ... any thoughts anyone?

My current kitchen has black subway tiles with white grout and everyone loves them. I bought my house with the existing kitchen and have changed the accent colour of the light shades and accessories from red to green in the last year (photo is pre green!) as I love retro mid bright green. Herb plants and glass containing cut herbs from my garden plus cheap black metal indust chic shelves that house lovely green china items also help soften the tiles. I would ideally change the benchtops from white laminate to med rimu type wood and steel, go for a darker grout for practical reasons and change the cupboards from this grey/dark brown laminate to lighter wood (not scandi white type though - I think is now getting dated and is to me a very cold style and not practical). I have my own style, love colour pops and I would best describe it as eco retro boho industrial chic - eclectic. Go for your style and if its not your forever house - think budget and what will be easy to update. I think subway tiles work well for updating and are classic but perhaps think colour instead of white or black as well and also grouting colour - it makes a difference.