The wife and I went on an activity holiday in Finland last year (Feb 2005). The cold is something that is hard to describe. Our nostril hair froze the first time we inhaled each time we went outside.
The clothing we used was as follows:
For activities such as snowmobiling, dog sledding etc.
2 layers of thermals (tops and bottoms)
1 mid weight fleece jacket (200 weight)
Power stretch fleece leggings.
1 insulation layer (all in one snow mobile suit though a good down parka would have done the same job for the top half and insulated/wind proof salopettes for the bottom half)
A balaclava and a Lowe Mountain Cap for the head
Double glazed goggles.
1 pair inner gloves (like thermals)
1 pair wind block fleece gloves
1 pair goretex over mits
3 pairs of socks
Specialist snow boots of goretex hiking boots (allow for a fairly loose fit as blood circulation will stop your feet getting cold)
For activities such as cross country skying, snowshoeing etc.
2 layers of thermals (tops and bottoms)
1 mid weight fleece jacket (200 weight)
Power stretch fleece leggings.
Goretex jacket
Fleece snood neck warmer
Lowe Mountain Cap
Sun glasses
1 pair inner gloves (like thermals)
1 pair wind block fleece gloves
3 pairs of socks
Specialist snow boots of goretex hiking boots (allow for a fairly loose fit as blood circulation will stop your feet getting cold)
In rucksack
Down Parka
Goggles
Goretex overmits
Spare fleece layer
Enough space to put any layers you take off.
Just a couple of tips
I spent the week continually dehydrated and have subsequently found out that you dehydrate by breathing, the air is so cold and dry that your body humidifies automatically. So drink loads of hot drinks.
The down side of this is that if you drink loads you need to pee and in all that clobber it is a pain.
We spent a lot of time adjusting layers, when we went inside etc. to make sure we did not sweat up, the sweat can freeze making you very uncomfortable.
Where we were (Kuhmo) the wind was not a great problem so wind proofs just help to keep you warmer.
The best piece of kit was the Rab Guide down parka and the goggles (they stop your eye balls freezing).
Finland is a fantastic place and to enjoy it to the full you have to rely on your equipment to keep you comfortable. We had a dog sled safari which has spoilt by me not being able to feel my feet!
I hope that this has been informative, I also hope you enjoy your trip.
Regards
Stewey.