In reply to Wonrek:
Nice work on the entry - after I did The Wall 18 months back I did think to enter this but thankfully I talked some sense into myself!
I was really into lightweight camping in winter for a while, so have tried a fair bit of kit. Things I didn't like were the Terra Nova Elite 20ltr sack. Horrible carry, really was unless it was crammed full. I use an OMM Adventure Light for weekends now, as I can just about fit everything in and it's comfy when running. My lightest cook stuff is a titanium mug (400ml), a small stove (coleman f1) and the littlest gas cartridge. Never got on well with meths.
Tent-wise - Vango Helium 100 was too small and had daft internal guys, Power Lizard was spacious but daft guying again. I use an old Laser Comp but in winter, I have been known to just use the outer with a groundsheet - loads of space to spread, cook and sleep but obviously colder. Some of the newer bivy tents aren't much different to that setup.
Sleeping bag, only you know how warm you sleep and it's hard to offer advice but you can get away with seriously lightweight if you have a decent winter mat. Working out which is lightest is when the fun starts!
Best of luck tho... psyched for you.
Kelvin