I usually just wear what I have... Dinner with my family is very casual - my grandmother and aunt wear aprons all day from all the cooking! LOLUsually i'll just wear a pair of dress pants and a nice sweater... at work we haven't really had any big parties like in the past - so that is pretty casual also. Unless we have a party this year, I'll probably just stick with my basics... but an excuse to go shopping is always good too!
Since I'm still in school I don't have office parties or anything like that .... I won't specifically buy something new for Christmas, but I make sure I don't wear the same outfit twice for the family gatherings so that I have a different outfit in each year of the family photo albums!
I always buy a new outfit for Xmas but that's coz i rarely get to splash out on myself (clothes wise) during the year coz i spend all my money on make up!
I ususally try to buy at least a new sweater or top. If I can, I'll buy a whole new outfit. I guess it just depends on how I'm feeling, and if I see anything that catches my eye.