What are the original countertops? That will definitely help if you are going for authenticity. I like the look of soapstone in "country" kitchens, but if there is a lot of wood you may want to lighten things up with something lighter colored. What color are the cabinets?

I would recommend a granite slab. That will keep the natural characteristics in your home and also give you an upgraded product. You could also do quartz that still has a more natural look like granite.

http://pentalquartz.com/collection/ this is a great link for quartz.