Round tables are an important aesthetic option, with some clear advantages. They are more welcoming, versatile, social and less annoying for diners: the legs are less uncomfortable and because there are no corners, we can avoid painful encounters. However, they require a very special space and are not suitable for crowded parties.
Dining tables and chairs absolutely need to be proportional with each other, as there's no use in having a low table and tall chairs! For a pared back, organic and very zen installation, Japanese designs can be looked to for inspiration, with tatami mats housing a low table and numerous floor-mounted seats. With back supports in place, comfort AND relaxation will be combined to perfection.