Visited Samui several years ago (chaweng) and loved it - the beach, the restaurants, the night life (green mango etc.) really friendly and laid back.
Thinking of going back next year but can't gauge whether it is still as good. Reviews seem to be mixed - is Chaweng full of drunken yobs? is everyone trying to rip you off? are the beaches filthy (to be honest people were saying this last time I went and they weren't)
Also are the summer months to hot for a five year old?