Bathroom Floor Tile and Grout Color

We are less than a month away from our master bathroom renovation. As usual, gathering and picking all necessary materials is no easy task. We've decided to use 12x12 polished Bianco Carrara as floor tiles, similar to what we did in our basement bathroom. The only difference is that I will be using either basketweave or herringbone as a framed accent area in front of the freestanding tub.

Now comes the tough decision: which grout colors to use?

I used Mapei's Unsanded Grout in White for my kitchen backplash. Tile is Bianco Carrara Mini Brick Mosaic.

Basement bathroom is rarely used, so I opted for the same Mapei Unsanded Grout in White on the floor.

I love how clean the white grout looks, but the master bathroom is probably one of the busiest area in the house, so a white grout may not be a wise decision in the long haul. I am thinking of grey shades that can be picked up from the tile itself.

Here are the three contenders: left to right, Mapei's Warm Grey, Silver and Pewter (the color strips above the cable outlet).

 Source: Flickr.

This is Bianco Carrara with Warm Grey grout lines.

Source: Flickr

Or how about this?

Source

I like that the warm grey grout adds more definition to the otherwise mostly white tiles, yet it doesn't scream for attention. I like it more from a practicality and low-maintenance perspective.

So would you use a grey grout with Bianco Carrara floor tile? A lighter shade of grey than Warm Grey maybe?