Opuntia engelmannii var. linguiformis
A common sight in Arizona gardens is the Cow's Tongue Prickly Pear. Folks like this cactus because of the unusual shape of the pads, which strongly resemble a cow's tongue. It can grow quite large--ten feet tall and wide. It takes little water, and has yellow or orange flowers in the spring that form along the margins of the pads, followed by numerous red fruits as seen in a previous post.
The downside of this cactus (or any Prickly Pear for that matter) is that after it matures, it displays a woody trunk that takes away from its attractiveness. One way to hide the trunk is to plant wildflowers near it.