Chiang Mai, in Thailand. A lot of the blogs I read about long-term travel have written about it as a laid-back student city, with a nice climate, friendly people and wonderful food. Most importantly, it's cheap!! I would love to just kick back, do some reading, cook and eat out when I felt like it, get caught up on some work online here and there, and just relaaaaaaaxxxx.
I'm sure I'll end up spending at least a couple of weeks there before FIRE, and maybe a few more afterwards :D