Koh Phangan if you want a bit of life, awesome selection of restaurants, nice beaches and cool spots to hangout. Also there’s a bitcoin community there or head to the more remote and island of Koh Phayam on the west coast that’ll take you back to Thailand in the 1980’s. Very cool and laid back spot closer to the Koh Surine Islands which are a beautiful spot to visit. 
Hit us up if you need a contact for sweet places to stay at.