So what do you sleep in when you camp?
I always carry an older, thick, Coleman sleeping bag made for approx 30 degree weather.  I also always carry a Falsa blanket (bought at a truck stop).  I now also carry an inflatable mattress (cheap), a small tarp (cheap), and a foam sleeping pad.  This is my basic preference for camping out in Louisiana most of the time.
In colder weather, I will have the tarp down as a floor and folded back into a lean-to.  The air mattress under the foam sleeping pad, with the sleeping bag on top of it.  I'll have a Falsa blanket, sheet, Falsa blanket, and sheet on top of the sleeping bag with me inside of the bag.  This provides great insulation and thus, great sleeping!
If I am using a tent, then I'll use the tarp as a ground sheet for the tent.
I roll up the sleeping bag, Falsa blankets and sheets, lengthwise.  I then roll the sleeping bag up inside of the tarp, and strap this under the backpack top flap and tie the ends to each side of the backpack.  I roll up the foam pad and strap it to the bottom of the backpack.  If I am carrying a tent, I'll strap it to the bottom of the backpack alongside of the foam pad.
I can carry less layers if the weather is warm and I can carry more layers if the weather is cold.