Also, we used Polyblend's "Charcoal" for the grout on the porcelain tile floor. There doesn't seem to be a Charcoal color for the caulk. What's a good substitute? A different brand? Thanks!

I also have read that Murphy's will "ruin" hardwood floors, in that it leaves a residue that prevents a new finish (when you are ready to refinish) from adhering. I was sick when my wonderful house sitter cleaned my Swedish finish floors with it. I also read it can soften/cloud the finish. I never was able to read/find what to do to try to undo the damage. They are fine now and it's been maybe 10 years, but don't know if they will ever be able to be refinished. ETA: here is something I found that might help: If you have solid hardwood with a urethane finish, using products like Murphys Oil Soap or Orange Glo can create a cloudy residue. To remove the residue, clean with a 1/2 vinegar, 1/2 water solution and a damp sponge -- Not overly wet. THEN dry with clean towels. Windex has been known to reduce the cloudy film as a 3rd part to this step... but you may have to do it every time you use water/vinegar Read more : http://www.ehow.com/how_4723640_effectively-clean-hardwood-floors.html

You do not want grout in that location. The company that makes your grout should be able to supply a matching latex caulk for this purpose. Typically however the trim is removed or cut away so the tile installs under it and this is never a problem.

As others have posted, tiles are specifically rated for slip resistance. With a tile as large as the one you are contemplating, this is critical for safety. Small tiles have a lot of grout so it doesn't matter. I have small basketweave marble tiles on my bathroom and shower floors and it is the grout which provides traction. Prior to my remodel I had 12" x 12" tiles and they were slippery as ice if my feet were damp. The only way to use them safely was to make sure that my feet were always on a mat. I also have a small urban bathroom so I was never not within hands distance of the vanity. Even with that I still had some dangerous skids and one bad fall when the housekeeper moved the mat from its usual place where I expected it to be when I stepped out of the shower.