I left the USA (I'm a US citizen, born in the US) for several years at a time under fairly different circumstances each time.

1997: I moved to Anguilla to (legally) get around ITAR and other stuff. Stayed until we had visa problems there, just before e-gold disintegrated. My salary was nominally $1500/mo with a bunch of equity and all living costs met; it was fine.

2000-2002: Sealand. Lived in London for a while, then out on Sealand. Traveled a lot. Startup. Was fun. Went back when it imploded.

2003-2010: Iraq/Afghanistan/etc., as a civilian company founder, and then defense contractor. Was...interesting.

I'd probably like to do Asia for a year (CloudFlare's going to open an Asian office before the end of the year somewhere, so that's an option, at least for weeks/months at a time), and probably someday Berlin for a few years at least.