The classic English Lavender. Silvery-green foliage with bright violet blooms. This is perhaps the most popular variety in the country - despite it being available for decades, it continues to perform and impress.
English Lavender (Lavandula angustifolia) are, by far, the most popular type of Lavender in the United States (and are interestingly enough not native to England - they're actually native to the northern Mediterranean). They are prized for their bold purple flowers and aromatic foliage. They also are the most garden hardy varieties available. Nearly any sunny and dry spot will do just fine.