I just posted mine in another thread about baseboards. I did an inexpensive tile for my walls that is in a color called Perla, just barely gray. Olympia Tile Piccadilly Series Carrara baseboard and chair rail. Yeah, floor is too busy for the marble, but it is too late to do anything about that. In the half bath I used a porcelain floor tile from The Tile Shop and baseboards from The Builder Depot. I saw no problem in mixing in a little marble to add interest to porcelain tile. Your plan to do the shower in porcelain will also be fine. But plain white subways might not be as interesting. Consider a touch of color, if you can see a tile that goes with your stone tomorrow.

I think using natural stone as your bathroomtile would be much better. I got my new bothroom just recently. Aand I made almost everything made of natural stone in my bathroom. they look so great . stone sink stonetub stonetitle and stone sanitary ware. I got them all from www.chinasink.com stone mosaics tile--http://www.stone-mosaics.com/ bathroom stone sinks--http://www.chinasink.com/ stone bathtub-http://www.stone-bathtubs.com/ I hope you like it. Here is a link that might be useful: chinasink

The only things that need sealing are the slate, and if you wish, the grout. You don't need to worry about getting a little on the edges. It doesn't completely keep the grout from bonding. Not by a long shot. But at the same time, you don't want to douse the edges with sealer, either.

I had the same dilemna. I have golden oak floors throughout the rest of the house, but I wanted a darker floor in the kitchen. I would have loved an rustic, wide plank wood floor. This floor would not have matched the floors in the rest of the house and I was warned that the transitions from one floor to the other would not look so good by the saddles. In the end, I decided to go with the wood look tile because it works better with radiant heat than wood. I am so glad we did. Between the children and dog it was a good choice for us. I still have to stain the saddles at the two doorways that lead out of the kitchen, but it will be fine. If I used any floor other than golden oak, I would have the transition issue anyway. Love my tile floor! So easy to maintain.