I use Hobbs products. 80/20, Polydown, wool, and I splurged on a couple of packages of silk but haven't used it yet. I buy mostly by the roll but for the wool and silk I have prepackaged queen size. I really love the look of a double batted quilt. In those cases I use a layer of 80/20 topped with a layer of polydown. It really makes the quilting pop beautifully and can give a faux trapunto look.
I have also used bamboo, which has lovely drape and is delightful to work with but not very environmentally friendly in making the bamboo into batting. I have had clients bring me quilters dream cotton, which is nice and Fairfield blend, which I find on the low end of battings. It used to be a great batting but now not so much. Very fragile and uneven in loft.
Finally do not underestimate "unconventional" battings. I have used an old wool army blanket topped with poly down. Very warm but also stiff and very heavy. I had a client give me an old comforter to use on a t-shirt quilt and the end result was just fine.
Sometims for batting you want to take into consideration the end use of the quilt. Experiment with different battings and use what you like or gives the look you like best.