I'm planning to do a Christmas and or New Year buffet/dinner.

Unfortunately I'm not sure what is open this year and information is hard to find.

Any recommendations for a good quality (price is not a real issue) buffet or dinner in a nice (resort) surrounding for those events ?

The Banyan Tree at Bang Tao were recently advertising a Christmas Day (25th) buffet at their Watercourt Restaurant which sounded quite good, though not cheap at 2900 baht per person (inclusive of a bottle of wine between 2 though).   Get further details from their FB page.

I took a party of 10 to Thanksgiving Day Dinner at Friendship Beach Resort and they were very happy with the food, music, and atmosphere/location (just off the beach).  Based on that I'm considering going for Christmas and/or New Years.  Chef Charlie does a very good job always.

https://www.facebook.com/FriendshipBeachResort

https://www.friendshipbeach.com