Last year Land and I met up in North Georgia for a motorcycle gathering. We were the only hammock campers, the rest of the guys either stayed in tents, rented a room, or just went home. It got down into the 20's both nights and each morning Land and I met at the campfire and chatted about how comfy we slept while the other guys were still shivering in their tents.
IIRC Land uses a BBWB w/ UQ and superfly pinned to the ground. Dont know what type of bag, I'm sure he will chime in if he reads this.
I used my HH w/ fly, Sierra Designs SFC Hibernator bag, thermorest, and walmart big blue tarp for wind. Once I got the pad situated I slept perfect. No cold spots, and woke up in the am feeling great.