During my lost years in Austin, I worked on and off at an aromatherapy shop called Sabia, so I'm an intolerant snob when it comes to lesser-quality essential oils, and artificially fragranced products that label themselves aromatherapy flip my rant switch. True aromatherapy uses distilled plant oils for therapeutic and purely pleasurable purposes, from running off a cold to easing flu symptoms to relieving work stress. Although it has been practiced since antiquity in one form or another, the modern version was discovered/invented in France by a perfumer who devoted his work to understanding the molecular properties of EOs. Wikipedia has a reasonably accurate account.
The Florame shop on Broadway is the first U.S. outpost of a reputable French company, which produces EOs from organic wildcrafted and cultivated plants. No, they're not as cheap as the perfectly decent brands at Whole Foods, but you can smell the difference. They also carry high-end and rare precious oils, such as true Rose and Helichrysum, and carrier oils such as Grapeseed, for making your own massage oils, etc. If you're not the DIY sort, you can explore the company's extensive skincare line. Highly recommended: Geranium floral water. The flu/cold bug that's been making the rounds this winter hasn't been entirely vanquished, either, so pick up a bottle of Ravintsara, which smells like a cross between cinnamon and eucalyptus and fights the spread of viral infections. I bought one of their small wooden diffusers and Grapefruit oil -- relaxing and euphoric -- for my office.
Don't be shy if it's all new to you: Shopkeeper Alain, from Paris by way of Mexico City, is friendly and informative.