Some herb and fruit trees are pretty enough to be ornamental plants. Here are two of them:
Variegated Calamansi / Calamondin / Citrofortunella microcarpa
The leaves of the Variegated Calamansi are quite striking. It brightens up the predominantly green foliage of the surrounding plants...
Variegated Cuban Oregano / Plectranthus amboinicus
Apparently this herb is used in Carribean cuisine. I haven't actually cooked with this - it seems a tad bit too strongly-scented. I like having it around, though - the leaf pattern is interesting and there's a lot of texture, too. The leaves are thick and succulent. It's very easy to propagate, too. Friends grow it at the base of a potted plant, to drive away aphids, in pest-prone plants such as Hibiscus.