Any personal structure you choose, a tarp above it suspended, to shed water and snow, will save lot's of heart ache, wished I had listened to my own advice. I use a coleman cot, keeps you about a foot off the ground. Some Shakespeare brand foldup chairs that have a decent rear slope and foot rest, really helped in a hell of a rain storm when the tent was leaking heavily, we were able to place the chairs where the water was not heavily dripping, and keep our sleeping bags around us.
See previously recommended layered theory.

Location, Location, don't be in a water collecting ditch, don't be under a tree when it snows heavy, don't be on a down hill slope, when you expect rain, don't camp on a beach you don't know the tides to.
I'm sure many more will chime in.
Good subject, I do like the canvas tents used by packers, but you do need a seperate mule or horse to pack them in, and good woodscraft to put them up. Something for a few weeks stay.