I got an overnight cargo boat from Surat Thani to Koh Samui. They charge a few quid to backpackers that want to make the crossing. A nice line of mattresses all lined up across the floor side by side. It's pretty minging but an experience in itself. Alternatively just get a nice fast catamaran.
See, that's exactly how I feel about curry. But not chilli. Funnily enough I've just eaten some (reheated).
It is possible to have extremely hot yet incredibly tasty curries.
Fly to Surat Thani, it has the port that serves the three island and I think Stevo said he found cheap flights to there.
I was a big fan of Chiang Mai, but if you're only there for a short break I'd do Bangkok and the three gulf islands.
My missus left her bag of shopping in a pub in Oxford on Saturday night. Time to go and retrieve it. This also gives me a chance to go to the Korean restaurant. This makes me happy.
I'll echo the sentiments of going to the three Eastern islands over Phuket. Samui, Koh Tao and Phangan have a good range of nice beaches, activities, and party time action respectively. They're all short ferry hops apart from each other.