Currently on Ko Samui, not necessarily my Thai-island-of-choice (I came to meet a friend).
But! a) there are some nice beaches to be found and, just as important, b) there's some interesting eats to be sniffed out too.
Looking for interesting local food is, strangely, sometimes easier in the more touristy spots. Sounds stupid? Yes it does. But more tourists = more Thai people (giving them massages, hiring them scooters and selling various tat etc...), and these Thai people tend to want to eat some decent grub come dinner time. So if you can find where they eat, then you're away.
For example: in my case I'm staying near Lamai - a pretty busy beach on Samui. There's loads of 'farang' (westerners) tanning their bellies, eating spaghetti bolognese & bombing around on scooters. But this, somewhat ugly, beach town does have a nice central market with tasty local grub on offer, and some really good looking fresh produce (will stick some pics up in my next post).
Yesterday I had lunch at said market & ate 'kanom jeen nahm ya'. "WTF is kanom jeen nahm ya?!" I hear you cry. Well kanom jeen are old style Thai fermented rice noodles and they tend to be eaten as a brunch/lunch dish accompanied by some variety of curry sauce / nahm prik, plus fresh vegetables and herbs. Far as i can tell there are hundreds of variations.
This particular one 'nahm ya' has fresh white fish pounded into a sauce made from, among other things, dried red chillies, grachai and galangal. The lady on the stall gave me a big old bag of fresh cucumber, cabbage, snake beans, fried dry red chillies & pickled mustard greens to eat with it, plus a big old twig of both Thai sweet basil and lemon basil:
The whole lot cost 35 Baht....about 70p!