Answers you get are really others personal preference. There really is no correct answer.

For me, I would not use 12x12s on that size bathroom for the walls. I like 6x6s for walls in smaller rooms and 12x12s on the floor. I do not think 6x6s up an 8 foot wall is boring. Very common installation. You can add some mosaics and accent pieces too.

I have been carefully planning my bathroom for about a year. My bathroom is the same size as yours. I am doing 12x12 tiles in the shower, up vanity (8ft) wall, and the floors. I know it will look fabulous darling!
Donna

I did 16x16 on the floor and 12x12 on walls.

for the next bath i am trying to find the largest marble tiles i can find. then i will try to use slabs for the walls (if i can afford it).

I did 12x12 tiles on my walls in a 4x8 bathroom, and I hate it. I learned to live with it. The room does not look correct...the walls look unbalanced due to the size of the room. Go with 6x6 on the walls and 12x12 or larger on the floor to add some variety to the look.

I have the same 12x12 tiles on the shower wall and bathroom floor, and matching 3x3 mosaic tiles on the shower floor. It looks great, but then, my shower is 4x5 and the bathroom floor is 19' long.

Also depends on your tiles. We found 12X12 Spanish tiles that we love, will use them diagonally on floor, 36" up walls, including the bathtub, and completely tile the walk in shower walls/ceiling. We also have matching mosaic (2X2s) for the shower floor, and bullnose. We chose a listello border from the same company. The tiles didn't come in 6X6.

The wall tiles other than shower are not extensive since the bathroom has tub on left side and the bump out from the adjoining closet, a window with heater below, a half wall with the toilet which is the back of the shower, and then around to a wall and the shower facing wall with a ceiling cabinet and vanity...close to the door.

Our tile designer and ourselves feel that the larger tiles will have a cleaner look in this small bath. Guess we will see in a couple of days! Also, I guess we can ask them to cut the tiles if they are looking weird.

Donna, your limestone bath will look gorgeous. I have some in my kitchen. i love the subtle texture on limestone. just make sure that it will not absorb water, stains and soap.12x12 and 6x12 will really nice. Make the grout as small as you can for a monolithic look.

pharaoh,
I have Azul Bahia in my kitchen and I know all about delicate stone. I know about the problems with limestone in the shower. I wish I had chosen porcelain in hindsight but I love this limestone. I have decided for several reasons that I am going to try and not use my shower and take baths only. I know that's crazy but it will make my life a lot easier. I plan on enhancing/sealing with stonetech Pro. I will be so relieved when this is finished.
Donna

of course, that azul bahia is a star!

I am glad you did not get the porcelain. I recently saw a million dollar apartment with travertine look porcelain. as you get close to it you see the pixels (dots)!
Neither the texture nor the look are authentic. Easy to maintain but nowhere close to the real thing...

The field tile of my fossil mural is a limestone. it is a gorgeous stone :)

We are using 12x12 on our floors and for the shower and some of the wall area we are using 8x12 and some 6x6.

I was going to use 12 x 12 on the walls also till I did some reading about adhesion problems on the walls with larger tiles. Then I questioned my decision. Anyone know longterm results of using large tiles on the walls? I don't believe they've been in widespread use very long. In the past smaller wall tiles were in fashion.

Any tile guys out there: do you have a large number of instances to base a judgment on?

I am doing 12x12's on the floor in a diagonal pattern, then doing 12x12's on the wall of the tub deck (about 34" high) and on the 4" wall next to the toilet nook (back of the shower wall). The wall tiles are stacked in a basic pattern but the floor pattern breaks this up. I'm also changing the grout on the floor and wall to give some variety.

The shower is broken up with a frame, but it has 6" tiles on a diagonal on the floor and ceiling (same as the floor tiles but cut down to size) and the walls are 24x24 tiles. The walls are porcelain and the floors and deck face are travertine. The tub deck is also 24x24 (undermount) and it's in the porcelain. The baseboard is the travertine with a polished edge set square like the tub deck and wall).

In my family bathroom I changed out the floor to a basic 12x12 pattern set square and then trimed it out in black granite (antiqued) in a 4" base board trim, with the tub and shower surround in 6x6 hexigon pattern.

I know it's more expensive to change patterns, but it does break up the look a bit as does trim (like you are planning). It's really all a matter of preference. And luck...if you can find an installer :oP

Our bathroom is 7 x 7 and we used 12x12's on floor and 2 walls. I love the bigger tiles. Here is a pic:

pkirkhal,
Your bathroom tiles look great. I'll play around with some other options just to be sure about my decision. I think I'll go to some tile showrooms and see how their 12x12's look. Maybe I'll cut a strip of 6x12's in the middle of the wall to break it up.
Donna