In reply to neilus:
I've had some truly grim nights out before I got 'ol fatty (Rab alpine 600). I have slept in -15 with a single z-lite roll mat and a +4 comfort temp down bag. The morning after I was completely destroyed and there were bits of ice in the dimples, even underneath me. I had to put on all the clothes I had with me and stick my feet in my rucksack (surprisingly warm actually). Now if this happened while out on a trek it would probably ruin the rest of the trip.
And now I realised you are probably at the airport...