If you have one formal and one casual dining space, you can really go to town with different chair designs for both. A casual spot will do best with sociable, comfy seating that naturally leads to conversation, whereas a formal setting is where you can play around with luxury fabrics. If you only have one dining room, you're going to need to combine all of these elements in one set of chairs, if possible!
A simple design, with simple chairs and plain table in an open space, with overhanging lamps exhibiting minimalist taste. Wood table lines are always in trend, the upholstered chairs in checkered print and white lighting create an elegant atmosphere.