I have the Subway Ceramics Avalon / Minas with a medium gray grout. And a Shaw's white sink, if anyone is considering that, by the way. (My contractor could have ordered it directly, but at his request, I went through a tile store, and by the time everyone had put their sugar onto it, it was OBSCENELY expensive.) I'm not an installation expert, but at least with the Subway Ceramics, the installers use little plastic spacers between the tiles (I think some others have their own spacers?) when they put them up, they don't do it freehand, so how much grout you get is a function of 1) the limits set by the curvature of the tile and 2) what size spacers they use. So you might be willing to go a little darker with a smaller grout line, or with a handmade tile that refuses to go close together, you might want to stay light. The traditional color is close to concrete. But most modern people don't seem to like that, so do what pleases you!

OK, so I bought my appliances but haven't gotten them delivered yet since my house is not yet ready, so I can still return something if it turns out to not be good at all. I chose to buy a white top freezer refrigerator with a smooth finish instead of one of those bumpy ones. Stove, dishwasher, and range hood (when I buy it) are all stainless steel. Why? Based on where the stove and dishwasher are in the layout of my kitchen, they are in more or less the same spot on their respective walls of the L-shaped kitchen, offering a symmetrical look. A stainless steel refrigerator, based on its placement in the layout, would look asymmetrical, so I wanted something in a more similar color to the cabinets. After making my purchase, I noticed that Craigslist and Facebook are full of people selling white refrigerators so I wonder if I should return mine and get one of those instead. My parents' neighbors also gave me a side by side white refrigerator that is just the width I need, and the height is fine, so I wonder if I should just use that one, but I don't know how it would be transported into the house.

Well, depends on the vibe you like. I'm a color and pattern gal. I'd totally splurge on a bed quilt to anchor the room and decorate around it. I love them, wish I had room for more at my house. The first photo you posted has the advantage of having both color and pattern. I think probably most of those do, have a solid side. I like that first one because it brings in two of my favorite colors--lake blue and sagey green. YMMV. The striped one has the advantage of having a little darker color than the walls so would add a strong accent. Really depends on what you like best, they are all fab. The one with the bright teal and lime green would take you in another direction decor-wise. That one has a more boho vibe. I like that as well. Honestly, I'm sort of a person who thinks that most of the rooms in the house should have at least the same feel. I'm not a fan of bedrooms having dramatically different decor, which can be an issue when you have kids who want a bold style for their nest. I get that. But as a guest bedroom, I'd try to go for a look that at least mirrors your overall home decor in some way, relates to it. Also the layout of the room. A tiny room would have different constraints than a larger one.

Sounds like you've been in the home for a long time. The living and dining in my one of my early homes was diagonal black and white; I loved it. Have you ever had the tile floor professionally cleaned? It is possible that the color you see is due to a build-up of product over the years. If that doesn't work, runners in the hallway can cover a lot of it. I've seen wood floors painted to look like black and white tiles. It may not be too far a reach to have them painted, if the right paint can be found.