Oh, and a few months ago, I was playing around. This is what came as the result :D

I agree with Diane's ideas! Grey is a nice color. The only thought I had on having a corner sink cabinet, you may not be happy with it in the end. You have a little corner, and the sink may be too small for you in the end along with not having any storage space. If you can't find any curtains that you love, try a cheap roller blind for now. It will give you a visual look and an idea if you want to stay with a curtain or going a bit modern with a patterned blind or even a roman type shade. It could turn the cozy look into a clean modern look. Framed mirrors are expensive. Call a glass company in your area and have them give you a price on mirrors. It might be quite nice to take the mirror down, and replace the wall there with a complete wall mirror to fit, stopping the mirror at the vanity, and continuing the mirror across the vanity between the sink and window. It will make your bathroom feel much bigger, even though you wont be able to see in the mirror over the sink. Close up the vanity doors with new door. Use props first (white poster to cover up the doors) etc. before you buy anything! Stick on tiles are a great idea! They clean nicely and look great. Although I wouldn't go with the wood look. Your bathtub tiles are old fashioned, go with a stick on floor tile that is easy to look at, try to get samples first. Remember Gray is a sleek clean modern color. It is not a cozy country color. If you don't like the grey in the end, maybe a real pale blue or butter yellow (that would be more of the cozy cottage look).

How about some stunning black wall sconce lights along the wall? Here's a very contemporary example... The soft grey is an excellent option, and will look stunning with green foliage against it. To give it a real 'look' I'd suggest installing some kind of black feature - whether this be painting the window frame & putting shutters either side, or the sconce lights, or a modern metal artwork. Perhaps even tall black plant pots either side of the window.

You are correct the place does and always will look a bit sparse when you only have blinds. The question with curtains is sometimes dependant on what climate you live in and I am not sure where you are so I am going to say. If you need curtains for heat go for a quality curtain to the floor with a fabric that is not stiff (as I discovered I now own after buying curtains off line for my spare rooms). The expensive curtains I brought for my living room have a softer texture and hang so much nicer. As I need Curtains / Roman blinds for heat I have backing fabric etc on the expensive made to measure ones, where as the cheaper ones are just thermals. If you only want to add a curtain for looks and do not require it for heat I would recommend going with a lovely sheer / half see through fabric that drapes really well, this will add a point of interest and you can colour match or add a loved colour to a bare - white on white - cream on cream - colour scheme.