This topic from Long and Short Reviews was a good one, although whether I could call what we do "traditions" is open to question.
For a start, having anything Christmassy in the house is limited until at least the second week of December. I always have an advent calendar (actually I have two this year) but the decorations don't go up until later because my husband, who is the one to put them up, is not a Christmas person. There are houses in our area that cover their entire place in lights, but we generally just stick to a tree and lights in the windows.
On Christmas Day we go over to the local working men's club with my in-laws for a drink before going back to theirs for Christmas dinner. My mother-in-law and sister-in-law are incredible cooks, so generally everyone eats enough to keep them going for about a week.
As far as presents go, this year we're doing a Secret Santa with my husband's family, so I'm only buying one present for family plus one for my niece. My husband and I will swap presents before we leave - mine will usually involve at least one surprise as I love surprises, but my husband is always well aware of what his presents are because he's not bothered - plus it's impossible to hide his presents around the house.
For New Year we go out to dinner and then usually go to the working men's club with my in-laws to ring it in. Apart from one year when somebody started a fight on the dancefloor, it's usually a great atmosphere to spend New Year in.
So what are your winter holiday traditions?