A good quality floor tile will be fine, provided they are well supported underneath with no air gapes.
it kind of depends on the room its going in and what kind of contrast your personal style is suited to. that said, id go with a light grey or a light tan. if its in the a kitchen, go with a darker color that won't show stains as readily as a lighter grout color.
Is it a pure white? If so your best look will be a white grout. If you have any coloring or haze of color in the tile pick up and match that as best as possible. The use of any other colors in a pure white tile will show as a checker board look on the floor. Maybe not so bad in a real light tone, but any time you go a grey tone it will jump out at you. You asked about type of grout, most likely you ll need a sanded grout and have to use a 1/8 th 3/16 th or a 1/4 inch grout joint.I prefer 3/16th myself and thats what I use on most all my jobs. There are a few (few) porcelains made to go tight together and you ll need a unsanded grout. These you can tell by the tiny beveled edge they ll have .. Any questions you can e mail me thru my avatar and check out my qualifications there GL
