Why HK? ....maybe you want a crazy Xmas shopping session? or you want to get a 25degree C Xmas eve in a street full of bars..etc.

right, the Xams is there in HK, well decorated shops for tourist, Atmostphere is build up on the street and TV. Economy goes well so everyone should be in the big mood of holiday.

I suggest you go to the famous peak in the evening, the view is spectaculr.
LangKauFong the local clubbing area is a must go for xmas eve.
Of course don't forget all the lovely shopping mall and streets....

I am from HK, living in doha..