Hmmm, that's really hard, because I haven't been to many places. At least, not to live for anywhere near long enough to be able to tell whether I'd like to live there near-permanently. I mean, going on holiday is obviously a lot different from being 'stuck' somewhere for ever, and I'm sure many places that seem really idyllic would certainly have their down-sides!
I'd probably end up settling in the highlands of Scotland. :P (Although only if my lottery money would run to a private helicopter, so I could still have a social life up and down the UK! )
Before settling down permanently in my gothic mansion on the edge of an isolated loch, though, I'd like to pay extended visits to France, Italy, Switzerland, Hungary, Latvia, Arizona and Sri Lanka.