Where would you recommend to celebrate New Years?

I'm asking because right before New Year I will be on Ko Samui (maybe Ko Phan Gan or Ko Tao), and right after New Year I will be on Ko Phi Phi. I'm not sure if celebrating New Year in Bangkok is worth the trip (arrive on Dec 31st, return to islands on Jan 1st), especially because Bangkok Airlines now have a direct flight between Samui and Kragi.

Thanks a lot!

If you are on Samui for NY Eve you will have a good time, I can't see any reason to fly to bangkok for NY Eve and then fly back down south again. Samui would be much more party time than Koh Tao, if you are into a lively NY Eve.

Stay in the south -- no reason to return to Bangkok

I heard that in Bangkok they have fireworks and mass celebrations. I would love to have a feel of New Year celebration. Big crowds are not necessary, but places being open at 2 AM would be nice.

How are the New Year celelbrations on Ko Phi-Phi, Phuket, or Ko Pha Ngan?

Koh Phangan / Koh Tao and Phi Phi would have celebrations but not obviously as many people and not so much in a central location.
These are muuch quieter places and although quiet beaches on both Samui and Phuket if you want lively Chaweng on Samui or Patong on Phuket would be much more 'party time'.
Phuket especialy Patong Beach would be packed, noisy, fireworks etc, bars normaly allowed to stay open until 6 am ( on Phuket anyway ).
When we lived in Patong on Phuket Christmas through NY was simply party time, packed full and lively. NY Eve on Soi Bangla and down to beach road would be very ( very ) lively !

Resort along oast also have their own fireworks so the sky is lit up from various places, out of those Patong on Phuket would be the liveliest.

On Samui Chaweng / Lamai I guess would be similar.

There is a full moon party both on Christmas and on New Year's on KPN. If it's not your thing, you may want to avoid it unless you stay on the northern coasts and definitely book asap (most of the Haad Rin areas are booked already for that period due to the party). Either way, expect full boats commuting to the party that entire week.

charneese. How fast are you going to the orient