You're going to love Barcelona. Incredible city throbbing with life, you can feel the pulse of centuries coursing through it.
I just went to Isla Mujeres today and on the ferryboat over sat next to a couple from Thailand who told me about an island called Similan, an untouched island off the beaten path, still pristine. I felt like I was handed a map by Daffy, the character in the movie The Beach.
May have to find my way there at some point. Do plan to make Chiang Mai my home base for a few months though.