You may want to think about what will happen if someone drops a pan or glass plate on the slate floor. The kitchen is a place where stuff is likely to be dropped. So the material you choose should be picked with that in mind. You don't want something that will crack if a heavy pan is dropped.
Wood and laminate are not good options if there is going to be water splashing out of the sink...
I wish I could remember the url for some of those home design things where you can paste in different colors/patterns for flooring, walls, etc. Something you can do if you have a photo program like Photo Explosion, PhotoShop, or GIMP: take photos of your kitchen and then look at flooring options. Find pictures of flooring options and angle them a bit and paste them in to another layer to see how they would look. Of course, samples would also be good to see how they look with your actual lighting and shadows.
I second the vote for pictures.
