My sister and I are both into scented candles and we have our favorites. T loves Voluspa candles and they are one of her signature gifts. I love Astier de Villatte candles which conjure up the world's most fascinating cities and neighborhoods.
My other favorite candlemaker is Dyptyque—I love how I haven't even lit the one on my coffee table and yet the whole living room smells wonderful. My favorite scent from this line is Baies with a rich scent of roses and black current leaves.
A tip for hard burn candles like this one: make sure the first burn is over two hours long. You'll want to see a pool of liquid wax reaching all edges of the candle before you snuff it out. This way your candle will burn entirely, from rim to rim, and not just in a column leaving a ring of wasted scented wax on the outer rim.
Another good tip is to have a candle snuffer or a wick dipper, which will extinguish your candle smokelessly and coat the wick in wax for easy relighting. (You could also use a nonflammable long skewer.)
What to do with the candle glass once the candle is done for? Well, I like how Emily of Cupcakes and Cashmere uses them as makeup brush holders.
[1. C. Lynn; 2. Emily]