Groundcovers and stepables are an important part of the herb garden. Herbal groundcovers such as creeping thyme and Corsican mint make fragrant stepables for garden paths, walkways and herbal lawns. They work well between pavers, in low-use areas of the yard, or as a transition from the path to taller plants beyond. They give "patio plant" a whole new meaning - not just a plant in a pot on the patio, but a part of the patio itself! The appeal of herbal groundcovers as a low maintenance alternative to lawns shows little sign of fading. We have a short list of favorite groundcovers that we have used successfully in our own gardens and have had positive feedback from customers in using them in their own gardens.
For many years we had Roman Chamomile (Anthemis nobilis) in the path of our Medicinal Garden. Chamomile is one of the oldest herbs in continuous use since the time of the Egyptians, who dedicated it to the gods. It forms a dense evergreen mat that smells deliciously like apples. This wonderful perennial grows to a height of around 6" and can take either full sun or part shade. The daisy-like white flowers can be used to treat the symptoms of colds and to soothe the stomach and nervous system. As a groundcover, Roman Chamomile has the benefit of being able to endure being mowed with a lawnmower or weed whacker to keep it at lawn height. After a few times of being mowed the plant will begin to dwarf making upkeep even simpler. Another superb medicinal that can be used as a lawn is Common Yarrow. 
But topping the list for the most desirable groundcovers and stepables are by far Creeping Thyme and Corsican Mint.