[BKLYNH2]

I would go for real slate (over the aforementioned peel and stick) no matter what its better quality. Slate can come in a variety of finishes that are both pleasant to the feet and aesthetically appealing, and not slippery either. It will naturally feel warmer than a tile floor, however you can also get a small heater which fits under the toe kick space of a vanity which will blow hot air low to the floor, they work well, are not super expensive, and you'll never see it. If you go with slate don't go with something that has a lot of variance in the surface as all the nooks and crannies will collect water deposits that will look like stains over time, especially if the water is hard.