One more picture of the sink area.

Those are great light fixtures! I would paint the walls an off-white or cream, including the outlet covers and vent. I would also paint the window trim, baseboard and shutters the wall color so there is a bit less turquoise in the room and for a less choppy look.

I would probably leave the medicine cabinet and vanity turquoise, and bring in two accent colors with towels, rug and artwork. It could be bright (yellow and orange) or subtle (navy blue and darker turquoise like the colors in this tile:)

My daughter has white tile and marble in her master bath, but had orange and turquoise towels, so the artwork and accessories bring those colors into the room. More pictures here: DD2 MBath

I like the color on the vanity and the medicine cabinet. On my laptop they appear as more of a blue/grey than turqoise.

Cream color walls are probably the way to go. I would repaint/replace the outlets and vent to match the walls. Maybe even remove the interior shutters and replace with a curtain or shade. You could pull out one of the colors in the tropical paintings other than the blue.

Honestly, I think your bathroom is already quite charming! I may be a little biased as my master bathroom still has blue fixtures (sinks and toilet, blue and white tile). Admittedly at some point I'll be replacing them, but for now I don't mind them. In your case, I would probably choose a cream or white paint color or pale grey. I would probably try to paint the vent under the window the same color as the wall (if it's possible) and replace the yellow-ish wall plugs with white (to match the one white one). If possible, I might try to replace or remove the light fixture above the mirror, but I really like the wall sconces.

I love your blue!

I really like allison's idea of cream walls and deeper turquoise/navy accents - towels, bathmat, artwork, vanity accessories.

I think you should look at new light fixtures. I'll take those turquoise ones off your hands, at no charge! LOL!

Very charming.

Allison has fantastic ideas. Definitely consider her suggestions.

Gray would be my first choice for paint color, but you would have to make sure that it goes with your counter-top. You can change the perceived color by changing the light bulb to a different color temperature, especially if you are using compact fluorescent. You can also switch to black or gray towels.

Lars

Those light fixtures are amazing.

allison had great suggestions. My first thought before scrolling through other responses was to go bright... yellows and oranges.