Is there a shower in the bathroom? If so, can you share pictures? Just looking at the photo you provided, the subway tile seems incongruous with the current style in your bathroom. To me a single wall of subway tile without corresponding elements in other parts of the room would look out of place. Just my two cents.

How wide is the vanity?

I agree with pricklypearcactus..what's your rationale in tiling that wall? if you're going for that slightly industrial look-your current space doesn't support it. All the rest of the elements just don't spell this kind of style

If you like white, but the granite and flooring stays-white would seem too bright and stark in comparison to floors and countertops, while floors and countertops will start looking "dirty" next to white. Your other elements are earthy..meaning the rest of colors fr the space should either be somewhat grayed as well (think for example "cream" or "tan" not white)-or, if you're very annoyed by the current look and want to change the vibe-either go full way, chaging other surfaces too, or, on the opposite, do just subtle changes-like hardware that's more streamlined, etc. That will support your choice of mirrirs, and future lighting. Style with bold art or/and bathmat with some strong geometry in it..you can play with elements like shower curtain etc..but don't bring as big and semi-permanent element so different to the space as the whole subway tiled wall, without it being tied currently to anything else in the space, nor in style neither in color.

(sorry for all the typos..)

I think it's a nice bathroom..you can tweak it just a bit to get your desired vibe, so it won't be out of place, but will be more to your liking.

Alternatively if your budget supports it, and it really bugs you as it differes from the rest of the house(how the rest of the house look like/what do you plan for it?) I'd look into bigger redo. I can understand being indefinitely annoyed by something that looks like it doesn't go with the whole concept of the house.

But installing just a lone wall of tile will make matters worse for both scenarios

either thread gently or commit to a different concept, that'd be my opinion

Below we've included some lighting ideas along with some of our bathroom designs that might help you with your dilemma.

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Additionally I think the mirror you selected looks nice and will work well with your vanity.

When you convert from a single light fixture to double, the center electrical box will be removed (leaving a hole) and two new boxes will be installed with wiring running to them. You would absolutely want to have this done before doing any tiling. Either way the hole for the original center electrical box will need to be patched.

When you install the mirrors, you will need to drill into the wall and either anchor into studs or insert drywall expanders to hold up the weight of the mirror. If you decide to tile the wall, the mirror would be removed, wall tiled, and then you would still need to mount the mirror on top of the tile by drilling through the tile.