could do two vanities with cabinet between.
blue floor. espresso vanity. carrying the tile accent through the backsplash.
blue floor matched with boldness elsewhere.
grey top half.
light grey-blue walls (not the cabinet color!). you could do a much lighter version of your floor color.
grey vanity top.
cabinets on the outside.
low-height glass shower door.
plummy-grey-blue walls with espresso vanity and light top.
bold blue color -- since you already have a lot of wood (the cabinets) in the room, you could capitalize on it: beadboard wainscoting with a chair-rail all in white, then you could do a deeper color on the top half. Not super expensive.
you could decide to take down the huge mirror, put up two smaller beautiful mirrors, and have more color presence in the room. It would also make it easier to get lights near the sink/mirror, which I would want in a bathroom.
this is the beadboard look I was describing -- just a different wall color.
you could take down your huge mirror, and have two medicine cabinets set in between the studs. It would get a lot of the stuff off the counter and give it a great finished look. also not expensive at all.
color idea: light bottom half; blue top half; just a mirror, and you could do a transom window at the top between the bath and bedroom. more light in the bathroom. perhaps a small-pane divided light window?
you could do light blue-grey walls, and then use artwork/yadda to connect with the brighter blue floors.
this is the type of blue-grey I was thinking.
crisp light plummy blue-grey.
since your vanity goes to the left-hand wall, does it/can it come with a left-side backsplash like this one?
you could do two espresso-stained mirrors to balance the vanity, if you do a light wall.