Maybe black or slate grey!!

Maybe black or slate grey!!

I was thinking penny tile also.

I would suggest a simple grey slate tile. No pattern at all. He trellis from the wallpaper is all you need in your powder room. The floor should not compete with it. If you want to create a bit more of interest, lay the floors in a brick pattern but that's all. If you are located in Canada, CIOT carries a beautiful charcoal slate that I can forward you the picture if you're interested. Good luck, Laura

The look you seem to be going for is sophisticated and classic. You said that the wallpaper you have is slightly less busy and you will also have the lower half of the wall covered in white paneling, right? Well, it seems to me that your best bet would be either the hex white ceramic tile with the inset thin black strip (bottom picture posted by Natalie above) or a version of white marble such as Bianco Carrera or even Calcutta Gold (still white). Very classy and timeless look. If you decide to change the wallpaper down the road, white marble goes with nearly everything. I definitely would NOT put in a black floor if you have white paneling at the bottom of your walls. It will be too visually disruptive. Try to think of it like clothing ... as if a woman were wearing a black & white dress (your wallpaper) with bright white stockings (your paneling) and then black shoes (your floor). It just doesn't "flow", in designer terms. The marble has a subtle pattern but will "flow" better with the paneling right next to it. Good luck Allison! Shari from Harmony Home Design

A grey penny round like this might be great - http://tiledaily.com/2012/03/01/matte-penny-round-porcelain-mosaic/

These brown/bronze varieties might also work - http://tiledaily.com/2012/01/18/rustic-bronze-penny-round-mosaic/
http://tiledaily.com/2012/03/29/brown-rust-textured-square-porcelain-mosaic/
Alternately, a dark grey floor also creates a great neutral feel that will allow you to enhance what's being done on the walls.
- http://tiledaily.com/2012/03/08/urban-matte-porcelain-series-grey/

Black Marble:)

HI --- Edge the room in glossy black marble , about 6 inch border then have white marble hex tiles in the center.A gold filler strip could be add between both for some glitter. Best of both with interest.