Grout joints, and tile question?

Question:What is the standard size grout joint for floor tile? 1/8-1/4-3/8/-1/2. I have seen them all I just want to know what to use on a 12" floor tile and what on a 6-8" floor tile. Also my bathroom is 6'x5' what size tile will look best.

Answers:
If you're using both the larger and smaller tiles together, go with 1/4 or 3/8. The larger the tile, the bigger the joint. When you're mixing, just split the difference. If you're going with the larger 16" or 20" tiles (especially the natural stones or terras) go with 3/8th or 1/2".