I'd vote for X3: Terran Conflict, if you are at least a bit into sci-fi. Hard to get started, but the reward is an incredibly atmospheric game that can last literally for months :)

Anything Russian. I'm getting into Metro 2033 now, I'd recommend that, also Stalker.

It definitely won't last "the entire winter", but there's no better time for Max Payne ^^'.

Agreed and with it being on sale on steam today, its the perfect time to get it

a wonderful suggestion! That game will take all the snugness out of being indoors shielded from the cold :p

What about Indigo Prophecy (a.k.a. Fahrenheit)?

TWO WORDS:
stalk. er.

Ski Or Die and Winter Games '92

STALKER: Call of Pripyat.

si piš :) for we are many!!!

so my specs are:
- Pentium 4 2,8GHz
- 2,5 GB DDR2
- ATi Radeon HD 4650 512 MB

yep, it's weak... at least The Witcher runs on in (well, it limps ;)

________________

thanks all for great suggestions, I've totally forgot about Max Payne or Outcast (the beginning ;), perfect settings! too bad I've already played all of them...

so I actually might try STALKER, demo first to see if I can get it running on more than 800x600 with LOW/LOW/LOW :D

and Ski or Die? :o) totally loveable game but I don't believe it would last the whole winter ;) but for a couple of hours, great idea!

AND there's always a chance that there will be a Normandy section in the new Deathspank that comes out today... :o) nevertheless, thanks!

You want atmosphere? Try Resident Evil 1....

How about a game from my "Top 5 EVER": Transport Tycoon Deluxe? There's an open source clone - OpenTTD - that actually works! It even has unofficial graphics packs, so you no longer need the original game to enjoy it. And it has winter levels/scenery too!

I'm afraid Resident Evil and Penumbra are not exactly the type of game I'd want to play while the snow slowly falls down behind the window, while sipping warm tea :D

(but don't get me wrong, they're great games! even though I've found myself unable to play Penumbra as I have to play it all by myself in my flat and I'm just too scared ;)

but one of my colleagues has pointed out another great game with deep winter missions today - Hidden & Dangerous! that might be a good thing to try :)

Oh yes! How could I forget about Hidden & Dangerous? You can get Hidden & Dangerous Deluxe (it's the first game and the expansion, but with a few good tweaks) for free on the internet. The second one is also good, though getting that one might not be as easy.

You know what I remember about Hidden & Dangerous?
Dying because I stepped off some stairs one stair early, thus falling about 1 foot.
Also, it was fun in co-op.