New mirror, light, hardware, and window treatment would be the way I would start. Is there a shower also?

Dark espresso cabinets, large 5x7 rug (if that fits), roman shades, 2 mirrors over the sinks instead of the large mirror, paint the walls a color that ties it all together.

How about wallpaper in some dramatic pattern? Then add new top quality towels and great rugs in front of vanity, shower and bath. Change the shower head to some luxurious style.

There's tile everywhere. Treat it as a neutral and ignore it. Or have it all painted white from top to floor if the change is worth the money for you.

I like the idea of painting or staing the cabinets a deep expresso color. the idea of placing something in front of the vent is a good one. a bench, taller plant. Also, a soft indoor/outdoor carpet that takes up a large portion of the floor will break up the tile and give you a focal point. or alternatively you can paint the caninets creamy white, paint the walls a nice clean seafoamy type color, and then anchor the space with a larg indoor/oitdoor carpet that pulls all the colors together. with either version i would most definately remove the mirror replacing it with two seperate framed mirrors. sconce lighting would look nice. but if rewiring is out of budget simply replace the lighting woth more modern fixtures.

Consider a long oriental that picks up the color of the darker tile (BM galt peach?) and then pick out one of the other colors from the oriental that you like for the walls. Pick the vanity color to coordinate. Put up a larger mirror that comes down to the backsplash. Choose a larger picture over the toilet.