I've finished installing marble tile on my bathroom floor. It's laid in the versaille pattern (see http://fp.vendaria.com/vpop/VpopView...tle=&pf=t&fr=t) The tiles are 8x8, 8x16, 16x16, and 24x16. It looks great on a large floor (200 sf). The thing to note about this pattern is that there are never 4 corners together, and there are no long straight lines.
I'd like to design or find a similar pattern for the shower floor. This is a 6x4' space. I'm thinking of something where the tiles would be large around the outer edge and get smaller as they near the drain. Perhaps this could be done by dividing up the large tiles into smaller versions of the same versaille pattern.
Also, it would add a nice touch if they formed a spiral, like water going down the drain.