The smallest shelter kit I have come up with to date.

2 person AMK Heatsheet
36" of duct tape, folded flat
30' of decoy cord

If a poncho is needed, take a 12-14" strip of duct tape applied where you would want a head hole, then cut the hole in the duct tape/Heatsheet. The duct tape reinforces the hole. More duct tape will close the hole.
Or use cord to rig up A frame or lean-to shelter, tape for repair, etc

I prefer a poncho, but that is because I am more likely to get caught in a sudden downpour and want to stay dry / keep moving, than I am to build a shelter / hole up.

But that is my needs, not necessarily yours. (I've actually got some little packs of a space blanket plus a poncho that Tescos were selling off cheap - small and easy, best of both).

Remember the rule of 3s - shelter is a much higher priority than food

IMHO I would vote for the AMK heatsheet. I have one in my go bag and I live in Florida where I am much more likely to encounter rainstorms vs. Freezing cold. The heatsheet can be used as an emergency poncho, great idea duckear I'll be adding that to my knowledge vault, and as a means of keeping warm. Living in Canada I'd think the likelyhood of requiring warmth would outweigh dry. Warm but wet equals uncomfortable, dry but cold still equals hypothermia.
Just my 2¢

-Bill Liptak

Poncho treattment a Ranger Rick deal?