December Honeymoon trip to thailand

I want to visit Thailand for my honeymoon in mid of December
for 7-8 days. I want to decide on whether Samui is better or Krabi in terms of
scenery, places to visit, night life, weather and safety. I would like to spend
first 6 days and then go to Bangkok (mainly for shopping) and head back home.
Its better if I get couple of places to visit during my stay, heard that Krabi
has many nearby places and thus my inclination towards it. Should I stay at
same place during first 6 days or hotel hopping would be better? Also wanted to
know which will be the best place to stay and any reference to one of the
hotels. Also suggestion on how to travel back to Bangkok from Krabi/KoSamui
would help.