This is the vanity color and style we have bought.

12x24 slate-look (charcoal gray) porcelain tile would look nice. Running Bond pattern.

I would use a much smaller-format version for the shower floor, though--more grout lines=less slippery.

Instead of matching your shower floor tile to your other tile maybe you should consider matching your shower floor to your granite. We used the same granite as our countertop for our shower base. It's an option that may be a little pricier but it has definite advantages. There are no grout lines, no mold or mildew, it is guaranteed (at least ours is) not to leak, it has a low threshold, and installation is faster. Ask your fabricator if he does stone shower pans/basins.
The link below is for the company we used but I am posting it just or basic information.

You can see most of our stone shower pan in the picture below:

Here is a link that might be useful: Stone shower pans

No we have the acrylic base for our shower, no tiles there. Just the wall in the shower.

What are the dimensions of your bathroom? If you have a fairly or small large bathroom, keep the scale in mind. You might want to use a straight lay on the floor in a medium tone color, then use the tile in a vertical running bond in the shower. You could add an accent band of small tiles in the colors of your granite running horizontally near the top (gray, cream and black would look nice or use espresso in there somewhere). Too much off-set (i.e., running bond) visually confuses or overwhelms the eye I think, especially in a small space.