I really like your stone countertops. What are they called? They seem to reference the stone wall (not sure if this was your intention but in the pics it appears to be the case).

I would lean toward something simple for the backsplash and let your stone countertops and stone wall shine. But it really depends on what your preference for backsplashes in general is. My personal preference is for a more simple/calm backsplash when the countertop has pattern/movement in it. So, I am in favor of the simple white subway tile you suggested. I'd do it in a horizontal running bond pattern (with matching grout). The stone wall has a horizontal pattern to it and I think the running bond backsplash would be a nice reference back to the wall.

I'll be interested to see what others suggest. :)

What about one of the grays that are in your stone wall and in your counter as a subway tile. I'm thinking almost like a rainmist colour. Just a really subtle matte (not shiny) light light gray to pull the stone wall and counter together.

If you go with reddish brown to pull out that colour in your counter that is all you will see in your counter - you won;t notice the subtle waves of the other colours.

I did a Google search on pebble tile and I was amazed at the variety of choices out there. One website had pieces that looked a lot like your stone.

I saw your stone wall and immediately thought of Falling Water Slate:
{{!gwi}}

Okay after I read your posts I would agree with you all that maybe a stone looking backsplash would be too much on the eyes. I am leaning towards subway tiles, probably white or offwhite. Will they fit in our kitchen? Here are backsplash pics I like the most:
{{!gwi}}From Kitchen

I really like this one I found, not subway tiles:
{{!gwi}}From Kitchen
{{!gwi}}From Kitchen

and of course the brown ones, but I don't think they will blend with the countertop well
{{!gwi}}From Kitchen

EasyPeasy: our countertop is Tidal White aka River White, White River or Valley White

Thanks all!