In my Greek Orthodox church we use the 25th. I"m surprised there's a Greek church there using the 7th of January. Now the Serbian and Russian Orthodox churches are still using the 7th and I never expect that to change.
The Greek's do follow the old calendar for Easter though.
It might be Russians I'm thinking of. Believe it or not, I'm the faculty advisor to the local chapter of the Orthodox Christian Fellowship. (Yeah, I'm not sure why they asked an irreligious person who has no ties to the orthodox church and who can't read a word of Greek to be their sponsor; I'm just too cool I guess.)
I do have a Greek colleague who recently became a US citizen. She helps us read the maps in the Odyssey, which my son was reading last year. But maybe I was confusing her custom with OCF. I know somebody celebrates it later because I always get emails about that.
Anyway, I like Christmas, but I like all the holidays, mainly because they're holidays. Good excuse to drink too much, eat too much, love too much, and spend too much.
Happy Holidays!