pick any color you like. that floor is very neutral.

navy vanity, tan walls, white trim.

or gray walls. depends on the tone in those floor tiles.

black vanity, gray walls

you could also do greens. Sage green vanity would look nice

I say this all the time on here, but check craigslist for people who are unloading bathroom vanities super cheap. sometimes granite top and sink included. or look for a remnant countertop you could use. mirrors, lighting,,etc. even leftover floor tile. learn how to demo and tile yourself.

Maybe find your shower curtain first? Here's one from C&B that might make a gray vanity play nice with the tan in the tile and floors. https://www.crateandbarrel.com/italian-seersucker-neutral-shower-curtain/s650694

I would leave the vanity which looks to be in good shape.

Beth H. - Originally, I was thinking black vanity, gray walls, white trim...I was worried abt the little beige/tan strip in the white tile. Wish I could replace with black.

PS - I’m doing my kitchen island in navy Hale. :-)

tan and black look fab together. don't worry about that . try and get a wall color in the same tonal family as that tan tile strip. Then I would do either glass shower doors (craigslist again! you can pick up some for $100. I sold mine there and they were in perfect shape) or a shower curtain w/some accent colors. if doing the tan and black, brushed gold hardware, faucet would be a nice change if you can swing it.

look into updating a basic bathroom on a budget. few blogs out there that did a great job. Mandy over at Vintage Revivals has the best redo's on a budget.

https://vintagerevivals.com/?s=bathroom

and so did this one:

http://eastcoastcreativeblog.com/2015/09/bathroom-makeover-blogger-vs-builder-grade.html

complete makeover under 1K.

a few more for ya

https://www.jennaburger.com/category/bathroom-makeover/