Best 20 degree and under sleeping bags?

[Wingin it]

If you aren’t packing it’s really hard to beat an old school canvas flannel lined 5 lb sleeping bag. If you are back packing that is definitely NOT the bag to use though.

[bradslam]

Katabatic Gear Flex 22 down quilt (900 fill power). Extremely versatile bag. I absolutely love this piece of gear.

[spin05]

VIAM Outdoors™ 10 Degree Quilts.  Going on year 3 of mine. so far so good

[Ricochet]

I wouldn't say it's the best bag because I haven't tried them all but I picked up a Cabela's Outfitter -20 on sale and slept comfortably in it down to -7. I appreciate that it's a bigger bag so I don't feel like I'm sleeping in a straitjacket. Wouldn't want to carry it very far, however.