What will the rest of the rooms style be?

English cottage. Exterior is Tudor

Cottage= River stone, Blue slate, crackled tiles. Whatever you pick I'd use something with a country flavor, not polished slab or shiney squares.

I would use a marble either carrera, travertine or something like that just a 6"to 8" around the fire box. Find a nice mantel piece again marble or a stone would be nice but wood will work. Treat the rest of the wall with traditional raised paneled wood. You can probably tell I like English traditional country manor homes.