Is there a base trim there? Is it some sort of rubber base or ceramic? I've attached a base I think would look nice, it is taller and has some detail. I also attached a door casing that is wider but clean lines. White trim always works. Compare your white to your floor tile, there are hundreds of versions of white- yellow white, grey white, beige white, greenish white, you get the idea. Try and stay in a similar feel. If your floor has a grey feel, look at more true whites or greyish whites,

I would recommend a soft gray...see photo below...

Hindware, Jaguar, and Roca have some nice basin collection. You should probably check out their website or visit your nearest store. Even though we suggest something online you might not get it near your place.

What is this space used for? Do you need brass to protect the walls? Who will polish the brass?