Share 'What is your favourite Essential Oil and Why?'

My first favourite would have to be lavender - so versatile and blends with so many other oils wonderfully. It's mild and relaxing. I also love ylang ylang - feel that it's a fairly sensual aroma but can be a little overpowering - a little goes a long way. I also enjoy the citrus fragrances i.e. lemon and orange, as they are so cleansing and refreshing. What are your favourites?