I loved Koh Samui in Thailand!
I would recommend staying in the Chawen or Lamai areas because they have good beaches, shopping, and night life. The Nora Buri Resort and Spa is perfectly located. I was really impressed by this property with its beautiful rooms, amazing pool, and great beach access.
I stayed at The Conrad, which was a resort where luxury is at its best. It's on the southwest side of the island called Thong Krut. If you are looking for seclusion, this would be a great place to stay, but keep in mind that you are far from anything in "town" and a cab can cost the equivalent of approximately $35.
Most importantly, the Secret Buddha Garden is a must-see if you can find it!
A word to the wise: be cautious of roadside elephant and monkey attractions because these animals are tethered and stressed. You're better off going north in Thailand. I can help you find elephants in a peaceful atmosphere.
Koh Samui has night markets all week in different locations, weather permitting, for great local food, shopping, and music. Because these seem to change a lot, the best way to find out when and where these are is to ask your hotel front desk.
Just a tid bit from my trip to Koh Samui! If you get a chance to visit Thailand, make sure to make time for this beautiful island... and let me know! I can make it happen for you.