If you could only pick one type of "ultralight cordage", what would it be?

The idea behind this is to pick only a single type of line for use in a pocket size survival kit. The goal is to pick a single type to use for fishing, snares, sewing, and other typical light cordage duties when the 550 cord isn't needed. This is also assuming you do not want to use the inner strands of the 550 cord.

The three best options that come to mind and that have been suggested in various posts include: Coat & Clark's Upholstery Thread, Spiderwire Superline fishing line, and Dacron (2) kite string.

I haven't seen true weight limits on the upholstery thread, but you can get the Spiderwire Superline and Dacron kite string tests up to several hundred pounds. The broad range under consideration is 50-200# strengths. For the sake of arguement, consider anything less as insufficient to use as snare wire and anything stronger as too bulky. But if you have a strong argument to make here, you'll probably share anyway.

If other equal quality ideas are out there, include them in your post. My question is, has anyone out there used more than one of these quality options? What are the pros/cons of each? What do you prefer and why?

Thanks as always!
GoatMan