Mysidia was one of the best servers at launch, and it still is. High population, an healthy mix between americans/europeans/japanese. You don't hear people bitching in shout in ul'dah on how the game sucks and similar bickering (which you do hear often in Besaid, mostly thanks to a certain undesirable), and I met a wide majority of simply nice people.

Anyway, good luck with the rebuilding whatever server you chose