Porcelain or ceramic tile only.

If it's a concern, the floor will have a lot of grout lines. Urine, basic grit and grime, etc. An alternative would be to use larger tile on the floor for less grout.

Or use an epoxy-type grout (or a non-portland grout) on the floor to prevent the grout from absorbing nasties.

Use the same material in each bathroom to minimize waste. You can carry cutoffs from one bathroom to the next.

If it's a factor, watch the lot numbers on the boxes. If you have to special order the tile for quantity, then be very careful when you order and when you pick up the tile. Check the order before it's placed, When you go to pick up, check the labels on every box. Though each store is different, some HD stores are notorious for having the ability to screw up most every special order.

Choose a tile that is rated to withstand the traffic you expect these tiles to get (see link to article below).

Make sure the tile is 'color through' in case it gets chipped from something hard dropped on it.

Also, compare the HD tile with tile from a speciality flooring shop before buying. When I did this, I was amazed at the difference in quality and quickly decided not to buy from HD.

Here is a link that might be useful: http://www.builddirect.com/Porcelain-Tile/Ceramic-Tile-Articles/How_is_Porcelain_Tile_Rated_for_Hardness.aspx

Wow.. Thank you for the good advice - I did not know any of this.

I just checked the tiles I had used in the past, the wall tiles are ceramic floors are porcelain. Does this sound right? Do you agree?

The PEI is 3 for the floor tiles. I assume I should get PEI of 5. Not sure where to find that though...

Is there a good online tile place you recommend? Home Depot is not that helpful once needing more specifics.

Use darker grout to hide the inevitable dirt. Or use epoxy grout. Or both.

Do you have a The Tile Shop near you? (www.tileshop.com)