Thanks zookeeper93! I am sure Travertine would be lovely. I tried out our shower last night and I have to say the flat stone tile was a great experience. It brings in nature, but a lot of natural stone does that to some extent.
At the planning stages I got in my head I wanted plank flooring in the bathroom. Initially I wanted all laminate gray wood flooring.
Then I found plank tile, and when we went to Lowes I found Style Selections Leonia Silver 6 x 24 Porcelain tile. Across from the Style Selections tile, I found a bin of stone tile. I settled with the gray river rock that fits the gray theme. When the river rock is wet it matches the charcoal mosaic from Style Selection and when it is dry it is closer to the Leonia Silver subway tile.
Another important decision I made was the natural gray tile grout. I was inspired by pics that use darker grout and my knowledge of how difficult to keep white grout white. The darker grout brings out all the cool lines of the tile layout. They gray grout also reinforces the gray theme throughout the bathroom.
Here is a link that might be useful: My Remodel Page on Pinterest
Q