I don't know what type of look you are going for, but here's what I would do... I would put white wainscot with a light airy blue/green paint on the walls above it. It looks like your tile might have some blue/green in it. That would give the bathroom a more spacious feel.

I'd do a gray grout. it will hold up better. if you want something lighter for the shower, try Mapei Warm Gray. have you thought about doing a warm wood vanity? with all of that gray, it will look rather 'cold' without something to give it some warmth. I love this warm gray oak one w/your tiles do a marble counter, or a white or gray quartz. if you don't want wood, then go for a black vanity. Or maybe this midnight blue one In fact, try looking at some of the wood vanities. Restoration Hardware. Black would look great too. I have marble in my bathroom and did black from RH or they have a metal wrap vanity if you want something more modern, try this white one

I painted our old, dark wood vanity with left-over Swiss Coffee over the weekend and after 1 coat I'm not happy with it at all. Too much white against the tiles and floor. This is a rental, so I have to make the existing elements work, but I'm stuck on what color I should repaint it. The counter is a sage green granite, green and orange backsplash tiles, I think the walls are Swiss Coffee and 60's white tiles with an orange border around the rest of the bathroom. Cabinet hardware will be oil rubbed bronze like the mirror, and new chrome faucet on the way. Should I go with a neutral beige, a yellower cream, or a light green/grey? I got samples of Valspar's Bay Sands and Canvas Tan yesterday, but think BS is too dark and CT too pink. Any recommendations are welcome, thank you!

A worn denim color came to mind when I first looked at the photo, but that is going to be a hard color to execute with plain paint. A bluish-gray? The background color in the vanity? I think this might be a room color you might need to tweak once you move into the house? It wouldn't be that hard to repaint.