Finding the right type of furniture, planters, accents and other garden knickknacks to set off a landscape design can take a great design and elevate it to another level. For gardens with a modern style, Design within Reach (DWR) is a great resource. They have a wide catalog of outdoor furniture and planters with a clean modern design aesthetic. Some of it is quite unique and almost over the top- great for adding a touch of whimsy to the garden.
Images below: Outdoor dining table with benches, Large plastic chair and modern ottoman.